Aquaponics and other things

The end of the experiment

2010-12-11T16:03:00.005+11:00

Some discussion first of the effect of the big rains we have had recently . Basically we have had a very wet spring and finally the drought is broken in our part of the woods.
The big dam had not been full for 10 years. However it has now been overflowing for more than a week and the huge rain of 2 days ago probably caused the water to be at least a foot over the spillway. This happened at night so I was unable , and unwilling, to go out and see how much water was running through the dam.
The picture of my Honda MUV and the road shows some of the evidence of the huge water flow at the time. The small 1000 litre tank on the side of the road was at the bottom of the gully and about 30 meters from where it is now sitting. And it is sitting just as I found in on the morning after the big rain.
We are counting ourselves very lucky as the rain did cause us some problems but they are minor compared to what happened to many others in eastern Australia at the time. The third picture shows the creek as it has been for a couple of days. It was clearly MUCH more destructive during the night in question. The section just down from the road crossing now has a gully which is at least a metre deeper that it was the day before.

And now to the aquaponics systems.
My reader will see that I have not posted to this site for almost 9 months and this may well be the last post .
Basically the systems have been only a moderate success and the workload is more than I can justify at this stage.
The main reason for the loss of enthusiasm is that in our climate the winters are too severe and the fish either die or simply stop eating during the colder months. Both of these naturally mean that the reward for the effort is rather small.
I have had ideas of building a super insulated, partly underground, greenhouse but they are on hold at this stage- simply too much work.
I have also had a fair bit of trouble trying to control white fly which really upset last years production in the big shed.
Actually notwithstanding the pest problems the vegie yield has been quite reasonable. The most successful plants have been peas and they keep cropping for ages provided they are harvested often.

However we have still not eaten any of the fish. The original silver perch are now about a foot long on average and the plan is still to catch and eat them.
The second lot of fish which were in the black tank in the conservatory have been caught and released into our big dam. They didn't grow well in the black tank. I am assuming this was because I was over cautious about feeding them. I had a few problems which I put down to an inadequate area for water filtration and so I tended to feed vary sparingly. When caught for release the fish were between 60 and 150mm long which is quite disappointing. And of the 200 initially put into the tank I caught about 100 for the dam.
With a bit of luck they will not have been washed out in the last week or so.
The black tank is now out of the conservatory and is finally ready to be used as a purging tank for the large silver perch.

The final nail in the coffin of the Aquaponics setup is evident in the picture of the main 4000 litre tank which is now well and truly out of the ground. Water running down the hill and behind the big shed has soaked into the ground and literally lifted the tank part way out of the ground. And it is unlikely to settle back into place as gravel has fallen down the side and presumably under the tank as well. Like all the other rain damage this happened a couple of days ago when we had about 80mm of rain overnight- on ground which was already well and truly soaked.

As you can imagine I have put a fair bit of time and effort as well as money into these aquaponics systems and I was keen to get some further use from the bits.
And so I am now using the smaller systems as hydroponics grow beds. I had planned to do the same with the big system but a complete rethink will be needed there as a result of the tank being out of place. The system is still sort of working but I am not sure that the big tank is not cracked as the water level seems unusually low. And the fine tuning for the float switches is all out of whack.
To date the small systems are working very well. Di has been harvesting lettuce from the first bed for some time.
Straight hydroponics is a bit of a cop out as I have to buy chemicals to make up the solutions but it is a lot less work.
I decided to change the gravel in one of the units as I am convinced that the original gravel I used has a lot of calcium buffering and blue metal is more common and accepted.
To date the first tank converted looks terrific and it has the original gravel but I have to keep adding acid to get the pH down below 7.
The second tank has the blue metal and so far the pH has not needed adjusting.
With lots of sun and warmer weather now here we are looking forward to fresh vegies for the summer. A smaller grow area but it does look promising so far.

Disaster??

2010-02-12T12:03:00.008+11:00

The second system, the big black one, suffered a major attack of a pest shown at various stages in the first 3 pictures. It is a little green grub, max size about 8 -10 mm long. Pupates ala the white cocoon and then hatches into a small moth which is also about 8mm long- rather boring appearence grey/brown colouration.

I have killed all the moths so can't take a pic for this post.
If I tried I could find a lot of the grubs and pick them off and then feed them to the fish. However I was not winning.

In a desperate effort to get this problem under control I decided to make some rhubarb leaf spray. A web search provided a number of different ways to make rhubarb spray . There was significant variation in the methods . However I made some but in my enthusiasm I have almost certainly killed off the bio filter in the grow bed. I did manage to kill most of the grubs and the moths but not before creating a new problem. You can see the current state of the growbed in this picture. A series of water tests have shown consistantly high ammonia readings which are bad news for the fish. We have been doing big (30-50%) water changes a couple of times a week recently. Might add the water is not wasted- it goes onto Di's pot plants which seem to be thriving on it.

It's not all bad news. The new GBs are doing well as shown by the last pictures. These were supplied with water from the main fish tank and are topped up daily with 5 or 10 litres of fishy water to ensure a supply of nutrients for the veggies. I have recently moved half a dozen or so of the Silver perch from the black fish tank into one of these new 250 litre tanks- they hide all the time and don't feed anywhere nearly as enthusiastically as the fish in the main tank.
The main plants in the new GBs are Vietnamese mint and a Habenaro Chilli as mentioned before. These are really too hot to eat for us but we have some slightly crazy friends who accept what we unload onto them when they see the plant.
As before the seeds for these new plantings were simply placed straight into the gravel. We only use seedlings when Di sees something she really wants in one of the many trips to the local nurseries. The habenaro chill was one such seedling as our attempts to grow plants from last years chillies were not successful.

Main system

2009-12-18T11:48:00.002+11:00

I should have mentioned in the earlier post that I have got the heaters running in the 4000 litre system in the big shed and the water has come up to about 25 degrees. This is costing about 10 Kwhs of electricity as expected but we have lots of spare and so it doesn't really cost anything extra. Clearly that is a nonsense as the system upgrade cost a bomb but I wanted to upgrade our power anyway and I got a 50% government grant to do so. Still nice to be able to do this sort of thing on solar power.
At this temp the fish are feeding like crazy so I will have to bit the bullet soon and try and catch some for eating.
My duckweed pond is also going very well. Lemna this time and not azolla. The fish eat about a cupful each night. I don't ever see them eating it as they are too timid but is it gone in the morning.

Another system

2009-12-18T11:19:00.003+11:00

As you can see the plant growth in the second system is quite luxurious at the moment. This is our salad vegetables plot and at the moment we are clearly not eating enough bushes. The fish are eating very actively and I have to restrict their food intake as the GB is not really big enough for 175 fish which are up to 80mm long.

I have now finally got the third system up and running. This is supposed to be the large fish purging system but we have still not caught any of the eating size fish. I have cycled the tank, with nitrogen rich water from the black tank system, and it is now stable with a low or nil ammonia level.
This was the original planned second system but the bits didn't arrive in time and so I built the black system shown on previous posts and in the first pic of this post..

This new system has another variation on the fill and drain mechanism. I am using a bell syphon to drain the grow bed instead of the float switch and/or timer mechanisms of the previous systems.
I decided to try bell syphons because I have had problems with the other systems as I have outlined earlier.
A bell syphon is a simple device which basically allows filling to a pre set level and then an almost complete empty of the grow bed back to the fish tank. The pumps run continuously. The full flood/drain cycle takes about 14 minutes.
I tried using a single 6 watt pump but it can't fill the GB fast enough to trigger the syphon so I am running 2 of the little pumps. I bought them very cheaply on eBay some time ago and have been looking for a use ever since. The top of the bell syphon is visible in the last pic.
This growbed is being used as a part herb garden and part seedling production area. Di has already planted out the pumpkins which sprouted in the gravel.
It is really easy to start seedlings in the aquaponics gravel. Just scrape a bit of a trench and sprinkle in a few seeds and wait. Provided the weather is warm enough you get plants within a week or so. MUCH easier than the seedling mix which has to be kept moist and the beds covered etc with the old fashioned way. And no need to transplant if the initial seeding was done in a sort of even way.

A long overdue update

2009-11-18T10:10:00.005+11:00

The last 6 months or so have been very busy for me as we have been in the process or upgrading our power supply big time. Many difficulties along the way with supply of bits. Plus the usual 1001 other jobs which need doing at the farm.
The new panels are above Phil and Ron. This picture shows an unusual weather event on 10th of October this year. Quite heavy snow for about an hour.
We have had a LOT of help from Ron Tito to accomplish this change. Actually Ron has been the driving force and without his advice and help the system upgrade wouldn't have happened.

And what has this got to do with Aquaponics you might ask?

Well..... it means lots of extra power to help me overcome some of the problems I have had with the Aquaponics systems.

The major problems I have encountered with the fish have been as simple as low water temperatures. Previous posts have detailed my efforts to get a sort of water heater going for the big fish tank. And to some degree (pun unintended) I have had some success. The lowest temperature in the big tank this winter was about 8 degrees and then only for a week or so. Last year it went down below 7 degrees and we had a couple of months below 10 degrees- and that killed all the catfish and most of the silver perch.
So the heaters worked vaguely as intended. I had to make a third one and I struggled with failing thermostatic control and cheap and nasty Rule bilge pumps but at least I haven't lost any of the fish. However another of the Rule pumps failed the other day and I decided to give up on that part of the heating system.
I have taken delivery today of 3 x 300 Watt Eheim aquarium heaters which I plan to put into the main tank in the very near future. These should be best quality if Eheim is as good as I remember from my Scullin aquarium days.
My crude calculations point to a 2 degree water temp increase for the input of 10 KwH of power. This was unthinkable before our power upgrade but we now have power to burn literally.
We have so much overcapacity now that the inverters are regulating power into the batteries as early as 10AM on most days. And we have a new wind turbine as well and wind turbines MUST have a load dump available so the fish tank will probably end up getting power from Jock as well.
Old wind turbine was Toby- a Swiss unit and Toblerone is Swiss- get it? Well Jock is a Proven wind turbine made in Scotland- so called Jock.

The other pics are of the plant growth at the moment. As you can see a bit of heat and things finally begin to grow again. We experimented with all sorts of supposedly winter plantings this year but the only things which can really cope are peas and silver beet. And the peas do really well so next winter we will probably plant all the beds to various types of them. The silver beet will stay as well as it just keeps powering on. These are now 2 year old plants which have provided a lot of chook food in that time.
We have let the lettuce go to seed just to see what happens. They grow too slowly to be much good to eat at this time of year and so the chooks benefit. They really love leggy lettuce.

And what of the big fish?
As usual I am unable to get good pictures and so you will have to believe me when I say that the biggest are probably more than 300mm long and ready to eat. I think I will try and catch them on a barbless hook. Only problem is I don't want to catch or hurt the smaller ones which are still only about 150mm long. There has been a huge variation in growth rates.

And what of the smaller system in the conservatory?
The higher minimums in this tank meant that the fish survived the winter but they haven't grown much. Now probably about 70-80mm long.
I think part of the limited growth we have experienced is due to my reluctance to feed as much as they might prefer. It has always been my philosophy that it is much better to underfeed than overfeed. Overfeeding is the quickest way to kill fish if any part of the system stumbles.

And a final pic of a fish which we found floating in the big dam in July of this year. It is a Murray Cod- about 600mm long and probably more than 10 years old. My nephew Ged gave me some mixed fish fingerlings quite a long time ago and I assume it was one of those. I was quite surprised to see this fish as we thought all the fish in the dam had died a couple of years ago when we had a big runoff event which made the water VERY muddy and probably suffocated the remaining fish.

New Fingerlings

2009-04-01T18:20:00.006+11:00

As the fish in the main system are almost big enough to eat I decided I had to have a batch of new fish ready to put in when the big ones are gone. And as Silver Perch are really only available about this time of year I ordered 200 from Silverwater as before. I doubt they would survive with the larger fish so I had to build a new system for the little ones.
I have ordered some fibreglass tanks from Murray Hallam in Queensland but he is rather slow to respond to orders so I decided I needed to build a temporary system.

So I cut up one of the 1000 litre IBC's I had bought a year or so ago to try and water shrubs we had planted out on the farm. Not enough spare water to use them at the moment for the intended purpose anyway.
I took a saw to both the steel frame and the plastic container to produce both the fish tank of about 650 litres and the grow bed of about 350 litres from the one IBC. The grow bed needs to be about 300mm deep and that was the reason for the proportions of the split. A system with this size growbed will only support a fairly small fish load but that is the plan anyway- the fish will go to the main system long before the growbed is unable to cope with the nitrogen load.

Then I welded up a support frame for the growbed which enables it to sit over the fishtank. I also added a pine platform over the steel frame and then several layers of expanded polystyrene foam- mainly to support the odd shape of the old top of the IBC which is now the base of the growbed. I glued the screwoff lid on with silastic and cut 2 drain holes to ensure complete drainage.The growbed sits directly over the fishtank and the drains drop straight into the fish water with drain which are exactly the same as those in the big system.

I didn't mention that I also decided it had to be in the conservatory to reduce the likelihood of low temps over winter which I already know are lethal to the fish. In the time we have lived at the farm the lowest temp we have recorded in the conservatory has been about +7 degrees (when it was -7 outside) and the water in the fishtank should not go anywhere near that low point just overnight. And so I shouldn't have to build another solar heater for this setup.

After setting the system up in the front corner of the conservatory I started washing gravel. With the first system I didn't wash the gravel as it was much too big a job and we couldn't afford the water. This time I didn't want muddy water for a month and I thought it wouldn't be too big a job. Another underestimation. It took me about 3 or 4 hours to wash 300 litres of gravel. Still I did it on the lawn so the water wasn't wasted- that is now the only part of the lawn that doesn't look like straw. I also stole about 50 or 60 litres of gravel from the main system in the belief that that would get the nitrogen cycle started sooner. As it turns out I have an Ammonia level much higher than expected at the moment, in the fingerling system, so perhaps that didn't work as well as it should have.

The plan for this growbed is that it will be herb garden and Di had bought the starter plants even before I had washed the gravel- talk about pushy!!

I am using a really neat electronic timer on this system which is currently set up to run for 6 minutes 15 seconds on and 50 minutes off. Both of these times are adjustable to the second and the big benefit is that I don't have to keep the water topped up as carefully to ensure proper flooding of the growbed.
The pump is a pond pump which can move 1000 litres an hour to the head I have on this system and it only draws about 14 watts so the total power usage is very low- much less than the big system which has a pump which draws about 400 watts for 9 minutes in the hour.
The fish arrived last Thursday and look terrific- about 40-50mm long and so far I don't think I have lost a single one which is quite a surprise. And they are hungry and come to the surface to eat unlike their big brothers in the big shed. I think this is because the growbed almost completely shades the fish tank- ie no sun on the water.
I am logging temperatures and water chemistry for this system as well so I will be able to compare the performance of the two systems to some degree.

It's HOT

2009-02-14T13:08:00.006+11:00

Today is not actually hot , in fact it is quite cool outside- about 17 degrees.
However it has been very hot this month in most of Eastern Australia.
The maximum here at the farm reached 36 degrees on 6th, 7th and 37 degrees on the 8th of Feb 09.
Fortunately we didn't reach 40 or 41 as they did in Canberra.It is always a little cooler here than in Canberra as we are at about 850 metres above sea level which is about 200 metres higher than Canberra.
The water in the fish tanks got up to a maximum of 28.7 on the 8th. Fish very active but it is at the top of their preferred temperature range.
And so I decided to turn off my little water heater as I didn't want to cook the fish just yet.
Unfortunately that turned out to be a mistake as you can see from the picture.
This is the 19mm black poly from the high point of the unit which was the heat collector for the pumped water from the fish tank.
I assume that the line didn't drain very well and the remaining water must have boiled in the tube creating steam and pressure which caused the blowout.
So I have had to make a third version of the heater. This one is basically the same as the last one.
I am getting faster at the manufacture but would prefer not to have to do it again. I think I will have to cover the whole unit with shade cloth if I need to turn it off due to higher ambient temps again.

The temperatures here have now dropped to the point where we have run the cooking stove at night- both to cook on and to heat our hot water in the house. Outside minimum last night was 6 degrees which is a huge change from the 23 degree minimum of the 8th.
And the fish tank has seen lows in the 15 to 16 degree range while the heater was broken. At these temps the fish are much less interested in food than they are at 25 to 27 degrees. There is no doubt in my mind that the heater is essential even at this time of year- even if just as a standby unit during the heatwave times.

My chillies are doing very well and are more than just decorative. The long skinny red ones , called Cayeene(?) are very prolific and Di has been using some in cooking. The label on the punnet said hot. And that is spot on. Only need one for a stir fry. According to Wikipedia it is hot:-
Heat: Hot (SR: 30,000-50,000)
It will be very interesting when we try the Habanero's which the label calls very hot. Considerable caution will be needed I think.
Wikipedia says of this type:-
Heat: Exceptionally Hot (SR: 100,000-350,000).
Habaneros thrive in hot weather. As with all peppers, the habanero does well in an area with good morning sun and in soil with an acidity level around 5-6 pH. The habanero should be watered only when dry. Overly moist soil and roots will produce bitter-tasting peppers.
I reckon I am doing most things wrong here- constant flushing with water, PH at 7.8. Looks like bitter peppers coming up. Will report on taste later. This assumes that enough can be consumed to give a taste other than fire!

The black pearls are also described as hot so I think we have good , if somewhat cautious, eating ahead. Interestingly some of the black pearls are bright red and some are black almost from the start while others start off green and gradually go black. The roundish ones in the 3rd picture are the black pearls. They have lovely purple flowers most of the time.
All the chillies were really put in because I couldn't resist the visual attraction of the plants.

We have had a bit of insect damage to some plants to date. The white cabbage moth is seen in the shed from time to time and is clear they are laying eggs. I don't have a picture of the moth grubs which are being a bit of a pest by making a feast of the asian greens. Mostly I don't have pictures because whenever I see one I feed it to the fish. And very much appreciated they are too.

We have also had something decimate one of the lettuce crops. It happened between my visits to the shed so I suspect it might have been grasshoppers. That is a guess as I didn't see any beasties. The affected plants are coming back so it is no big deal.

Fish finally growing

2009-01-19T17:02:00.006+11:00

It is now the 19th of January 2009 and we have only had 2mm of rain for the whole month. Not surprisingly everything is looking very dry. Now 8 years of drought and little sign of improvement.
I am again very aware that this aquaponics thing has to be one of the answers to the water shortage problem. We had a new water tank installed today, up the hill behing the house, and this brings our potential fresh water storage to 63000 gallons or 285000 litres . At the moment we are at about 50% of total capacity so we are now hoping it rains soon or the lawn and gardens will really start to suffer. We have been unable to draw from the big dam for several years now.

I have to add an extra 50 litres of water a day to the aquaponics fish tank, at this time of year, to make up for evaporation. This water comes from the 22,000 litre tank attached to the big shed which has the AQ setup. I have been carefully measuring this top up water for a year and have added almost 8000 litres in that time- slightly less than I had guessed would be needed and not bad considering the fishtank holds 4000 litres.

Had a problem with my little solar water heater setup for this system. I have no idea how but the poly pipe blocked up completely and I spent hours trying to clear the blockage. Used the big pump and lots of compressed air but I was unable to budge the blockage. I could even see where the pipe was distended. Unfortunately I had done too good a job of sealing the glass top to the heater and I can't work out how to lift the quite thin glass without breaking it.
So I had to make a new heater. I had actually planned on some improvements anyway so It wasn't quite the disaster it might seem. The new one looks a lot like the old but has a layer of expanded polystyrene foam under the absorber plate this time. I used the old plate from the original HWS heater- it is aluminium and painted black. I had a few problems with the poly pipe kinking but eventually I got it to sit properly. I have covered the whole thing with a clear, very heavy duty, PVC sheet about 1 mm thick. I also added a little filter to the line after the pump. This is one of the poly ones usually put in irrigation lines to stop drippers from blocking. It is too fine for the job and requires cleaning most days so I will experiment with various alternatives. It may not really be essential as I can open the heater and simply cut and rejoin the pipe if a blockage happens again.
As far as I can tell this new heater is giving me an extra 3 or 4 degrees in the water tank each day and daily minimums are now up to the low 20s and maximums have reached 27 or 28 degrees on hot days when it have been up to 35 degrees in the shed.

This increased water temperature is what I really need for the fish and they are now growing quite rapidly. They are eating voraciously. Mostly pellets with the occasional treat of worms. The pink things in the picture are the worms from one of my worm farms.
These are the same worms I introduced to the grow beds. Somewhat surprisingly they survive and breed in the GBs despite complete flooding of the beds every hour.

The biggest fish must be close to 200mm long by now while the smallest are probably close to 90mm. The big ones could be eaten now but I feel it would be a waste while they are growing so fast. Perhaps big fat fish dinner for Easter?? I will have to set up a purging tank before then and also work out how to catch them without damage to the others.

The bushes are growing well. My chillies look great and the tat soi and pak choi are doing the right thing. We have had a lot of spinach and sugar peas. Actually the spinach goes to the chooks.
I am now quite sure that the shed doesn't get enough light but we are learning the plants which can benefit from the current setup. For example lettuce grows slowly and really isn't worth the bother as it becomes bitter when grown so slowly. Still that's another "failure" that the chooks appreciate. It's all about finding the right balance.

Perhaps I am winning.

2008-11-20T11:10:00.006+11:00

I will begin this post with another gratuitous picture.
The deer in this shot have been transient in this area for several years. We have seen one or two on an infrequent basis. However in the last month or so they seem to have taken up residence. And in somewhat larger numbers. I first saw, and photographed, this group of four on 27th of October of this year at 7.30 in the morning. And now they have started to appear all over the place. We now seem to have a group of five or six who can often be seen down near our bore. And the resident mob don't include the two bucks seen in this picture. And I had to dodge another one when on the way into town a couple of weeks ago- in the mid morning. That animal was about 8 or 9 clicks from here on the road near Little Burra Road. So far I haven't noticed any roadkill deer but it is probably only a matter of time.
I suppose we should be attempting to control deer as they are feral but I can't bring myself to do so. Bit too cute and cuddly. Also it would be a waste not to eat them if shot and I don't really fancy the whole business.

And so back to the aquaponics.
In the last month or so things seem to have finally begun to show the sort of growth in both plants and fish that I have always thought were possible.
My little heater for the fish water is getting the temperatures up into the low to mid 20s and this is clearly better for the fish. They are eating lots of pellets and on one or two occasions were so hungry that they even came to the surface for food. This is unusual with my Silver Perch which would have to be the most "chicken" fish I could have picked. Some guests don't believe that I have fish as they have not seen them- even when standing right next to the tank!
I have again tried and failed to get adequate pictures- the fish are too nervous and the light levels are too low. Even my new "you beaut" digital SLR camera can't catch them. However just to prove that they are there I have included a fairly poor shot taken a week or so ago. The biggest are probably now close to 140mm in length- basically about a hands length long and perhaps half a hand wide. They are quite deep in the body. When viewed from above they look to be perhaps 25mm or so "fat". The smallest are still only 60mm or so long- looks like we will have a good long period of harvest. The white stuff to the left of the picture is out of focus azolla.

The vegies in the grow beds are growing well- we have had lots of peas and lettuce so far this month. The asian greens are again doing well as is the spinach. I have also planted some chillies for colour. Went shopping to a garden centre the other day and I couldn't resist them.

I am convinced that my last major problem with the whole setup is not enough light. The plants grow but they struggle with , at best, only 4 or 5 hours a day of full sun. I don't want to put more polycarbonate onto the roof- it is a shed after all and sun in not good for all the other things stored in there. Solution may be to simply grow plants which tolerate lower light.
The last picture shows various lettuces and some beans and peas which are doing well. This is the third lot of peas Di has planted. Actually it is the fourth but the third turned out to be sweet peas which were incorrectly labelled.

The outside azolla production is going very well. I am no longer harvesting and drying for the fish as I have a 10 litre bucket of dried leaf in stock. However the new chooks go bananas over fresh azolla. So they get a small bucketfull most days. All from the 1200 litre stock trough. The growth in the blue barrels is disappointing and I will have to work out how to improve that. I suspect that the water gets too hot as it is shallow and in full sun- perhaps a little shade cloth cover might be the go.

We had about 7mm of rain last night but it is still very much drought here and again I am reminded of the need to be conservative with our water. And so aquaponics must be one of the answers.

Warmer weather

2008-09-29T14:02:00.003+10:00

Finally some good news on the fish front!
The water temps are now in the 16-17 minimum to 19-21 maximum ranges and as a result the fish are feeding voraciously.
I was worried that a diet of live food over winter might have spoiled the little fishie palates to the point that they would not eat the pellets which are the main food source.
However the first offering of pellets was eagerly accepted- as was the first seasons chopped earthworms and my home made formula (liver, eggs, prawns and azzolla).

I reckon I only have about 40 or 50 Silver Perch left after the winter. And I can't see any of the catfish so I suspect they all died. $300 down the drain so to speak.
I don't yet have a good picture of the fish as they are very reclusive most of the time. However I have indulged myself with a new camera which promises(?) more manual focus and so if I get the time of day right and there is light in the right part of the tank , I should be able to get some shots. The biggest of the fish are now perhaps 100 to 110mm long and looking good!! Given that they are Survivors it is almost unfair to consider eating them - but I think we will manage to do so- perhaps even before next winter.
Actually on a slightly gross note- the dogs discovered that I had thrown the dead fish out onto the ground in front of the shed as I scooped them out of the water. And so they ate all they could find.
Even after I realized this was happening and started burying the bodies the dogs dug them up if I was not watching. I guess it is all just good use of the protein.

The warmer weather has also restarted the growth of plants. The peas Di planted in June of this year have finally taken off and we are now picking lovely fresh sugar snaps. Some of these even make it to the kitchen for cooking.
The top 2 pictures show the attempts made by the peas to escape the shed. Some are perhaps 6 or 7 feet high.

The coriander visible in one of the beds , in the bottom picture, is entirely self sown. We left the first lot of plants to go to seed and clearly the seed was dropped all over 2 of the grow beds. This really bolted last year and I doubt if we will leave it in the growbeds for as long this time as we will want the space for all the seedlings which are now coming up.

Di is really the gardener so I am unsure what is planned for this year. However planted seeds so far, and this is really just in the last 2 weeks, include several varieties of spinach, several types of tomatoes, various asian vegetables and other assorted bushes.
We put some spinach seedlings in during June as well and they did absolutely nothing until the last 2 weeks. In truth they didn't do nothing- most of them keeled over. However 3 or 4 survived and now thay seem to be away.

In general I feel that I have proved the concept of aquaponics as viable in this area with one major proviso- I MUST find a way of keeping the winter temperatures above the deadly lows of this winter.
I am reasonably sure that an improved version of the current heater will be worth the effort. I plan to add more insulation, longer length of poly pipe in the box, black paint on the inside of the box etc etc.
I am however also again planning a heavily insulated, partially buried glass house. Needless to say the amount of effort needed to build such a building just might scare me off- but I doubt it!!

Water heating update

2008-08-19T17:04:00.003+10:00

Just a quick note to record the apparent success of my little heater for the fish water.
My last post detailed the construction of a very simple black polytube heater which seems to be doing the job!!!
After about 2 weeks of operation it looks like the daily addition of just 1 degree of extra heat from the unit has raised the daily minimum temps , in the fish tank, from a low of 6 or 7 to a low of almost 10 degrees now. Still not warm but I think I am finally winning.
This new heat is a bit late for all those poor little catfish but next winter things will be better!!
Yesterday the minimum was 9.6 degrees- but it was a very cold day- it actually snowed quite heavily for about 15 minutes!! At the time Di and I were working in the chook yard making a new house for the new silkies- but that is another story.

I have also added a timer switch to the big pump setup so that the water is only pumped to the growbeds between 8AM and 8PM. The reasoning here is that the growbeds cool down during the night and so will tend to chill the water passing through them.

I have also got the differential switch working and so I don't have to go down twice a day to connect the 12V pump running the water to the heater.
Needless to say all is not quite a bed of roses- the pump draws more power than one 20watt solar panel can comfortably supply and so I have added a second 20watt PV panel.
This problem should be fixed soon as I have a mini maximizer kit which I will build and install when we get back from our little holiday to Hong Kong. This kit adjusts the voltage from the panels to enable a much more efficient conversion of the power from the panel to the load.

Winter Woes

2008-08-07T13:29:00.006+10:00

A totally gratuitous image to start this post- this was the view I had when I wandered over to the big shed this morning to check on the fish. The local kangaroos are almost tame- certainly not much bothered by us- or by the dogs provided we keep the dogs close to us.

The period since my last post have been a series of learning experiences- most of them not good.
As we are still in winter the temperatures are still low- both outside, in the shed, and much more significantly, in the fish tank water.
My reasoning for putting the fish tank in an insulated hole in the ground were based on the assumption that the water temperature would be more stable. This has been the case. I also thought that the lowest water temps would be somewhat higher than I have actually measured.
I have been recording all sorts of details including maximum and minimum temperatures in both the shed and the fish tank water.
To date the lowest room temp over the last two months or so has been just above freezing. Night time temps have often been below 3 degrees C in the shed. Daytime temps have been as high as 17 or 18 degrees. And the daily fluctuation has been as much as 15 degrees or so.
At the same time the lowest water temps have been in the 6 to 7 degrees C range with a daily variation of less than 2 degrees. So as far as variation is concerned the buried tank works.
However the stability is a bit of a two edged sword- the tank doesn't heat up much without help from me.
At the start of this adventure I chose Tandanus tandanus and Bidyanus bidyanus species as the literature suggests that they will both survive temperatures as low as 2 degrees C. Perhaps well fed adults will but little fry clearly will not.

I think I have lost ALL of the Tandanus and perhaps another 10 or 15 of the Silver perch.

The highest numbers of deaths almost always follow the coldest days.

On a positive note the fish are still eating some Daphnia which fortunately is in good supply - they refuse all other non live food. They even reject chopped earthworms which were a favorite in warmer times.

I have even contemplated growing trout next time- however that probably won't happen for another reason- the lower temps are not only bad for the fish but also for the bacteria which are responsible for changing the fish waste into plant food.

The growth of the current plants has almost stopped. I doubt if this is due to a lack of nutrients as much as simply a medium which is too cold. I reckon that in a dirt garden the soil can soak up a bit of heat from the sun and this help the plants. My plants are constantly bathed in coldish water. Perhaps I need to do some more experiments in this area.
Having said the above- all is not doom and gloom- the peas are sort of growing. And the tat soi has a bunch of pretty flowers. The tomatoes have all been removed.

And so I tried to adapt an old hot water solar panel heater to heat the water. As the solar panel has copper pipes and connections and copper is known to be toxic to fish I decided to make a heat exchange unit to transfer heat to the fish tank water without allowing the water heated in the solar panel to come into direct contact with the water in the fish tank. As the water in the heater panel would be subject to freezing I also used a glycol solution in the system. Glycol is also toxic to fish but I reasoned that the circulating water would not come in contact with the fish water so this would be OK. I made a big loop of plastic pipe to immerse in the fish tank and tried to pump the antifreeze solution around the system. Short answer - it didn't work- too much trouble getting the air out of the system etc. And the heat transfer ability of the plastic pipe is terrible. (Can't use copper for toxicity problem mentioned above, couldn't find aluminium pipe and stainless steel tube is VERY expensive).
So I have now made a much simpler heater for the water.
Basically it is 30 meters of 19mm polypipe inside the box that had held the first solar hot water heater panel. The water is simply pumped out of the fish tank through this polypipe and back into the fish tank. Crude measurements of water temp suggest that on a good sunny day, even at this time of year, I am getting a 1 degree increase in water temp during this pass through the unit. The pump I am using is a 12volt bilge pump rated at 350 litres per hour. The power for the pump is a 20Watt solar panel , a Solarex regulator and a couple of 20Ah sealed lead acid batteries. I am now trying to fix the differential heat switch which I am using in an effort to automate the process of pump on and off switching.
My current thinking is that I might be able to keep this heater going in the summer to get temperatures which should cause explosive fish growth. And perhaps even prevent the lows of this winter by "loading" up the tank and it's surrounds during the summer. Time will tell if this logic is sound or not.

To add to the problems I am having I have discovered, in the last couple of days, that the float switch which turns the big pump on and off has stopped working properly. Actually it is worse than that - it works intermittently. With a bit of luck a little adjustment to the weights and levels of the cables will fix this problem.

Cold weather

2008-06-17T15:39:00.006+10:00

It is now officially winter where I live and it certainly feels like it. We have had a few frosts and most of the plants in the dirt garden are looking much the worst for it.
The tomatoes in the growbeds are still alive and there is still some fruit ripening on the vines. They look pretty sad as plants and I think this is probably due to some mineral deficiencies which I am attempting to remedy with blue metal crusher dust. I am told that basalt dust contains all sorts of mineral which will slowly become available to the plants. To this end I have mixed about 8 or 9 cupfulls into each growbed. Too late for these tomatoes but perhaps of use to the next crops.
Di has put in another crop of peas and they seem to be doing quite well.
This is despite overnight temps in the shed dropping to as low as 4 degrees C.
The water in the fish tank is now around the 10 degrees C mark and the fish are not eating much.

The fish are refusing everything except daphnia at the moment.
Fortunately I have found a source for good quantities of this and I collect a couple of litres of daphnia every week or so. I then put this into the spare water trough I have outside the shed and scoop out a couple of tablespoonsful daily or at least every couple of days. As it is alive this doesn't cause any problem in the fishtank if not eaten straight away. The picture is one I found on the net and looks just right. The dark "balls" inside the daphnia are eggs or the equivalent. These little critters are only a couple of millimeters long so are really just a viable food for the fish while they are at their current size of between 50 and 100mm.
On that note I have had the fish for almost 8 months and I must say I am somewhat disappointed in their growth rate. It looks like we will not be eating fish until next Autumn!! If then!!
As they are still so small it is simply amazing how much plant growth we have had. I can only assume that when the fish are almost at the harvest size that we will have riotous growth in the growbeds and will probably have to plant and harvest like crazy.

The 3rd picture shows the second
plantings of peas .
Peas were quite successful the first time around. As it is winter I expect this planting to be a bit slower to grow than last time but we will see.
Nothing quite like chomping on fresh peas straight from the bushes while doing fishkeeping chores. Enough still make it to the kitchen for stirfrys and the like.

The final picture in this post shows
some Tat soi which we are letting go to seed as Di couldn't find new seed for next time. This is an experiment and I don't know how succesful it will be but it is worth a try. And the flowers are quite pretty.
We let some coriander go to seed earlier and a few little plants have popped up in one of the other grow beds.

Insulating the growbeds

2008-04-25T17:25:00.003+10:00

Today is Anzac day and that is traditionally the start of winter in this area.
I have been concerned for some time about how the fish will fare during the winter as it gets quite cold here in downtown Burra Creek. (Actually there is no town of Burra Creek- it is almost all ex farming land - never great farming land and now mostly hobby farms).
Already the nighttime temps are dropping below freezing outside and we have had cold enough weather to kill off the tomato plants which were growing in the dirt garden.

I had always intended to insulate the grow beds as they are above ground in the big shed and as the air temperature there is now dropping to as low as 6 or 7 degrees Celcius it is clear that the water temperatures will eventually drop as well. Current water minimums are in the 13 to 14 degree range so the tank insulation is clearly doing what it is supposed to do.

I had intended to wrap the growbeds with a product called Aircell which is a lot like heavy duty bubble wrap with a layer of heavy aluminium backed sisalation like material bonded to the bubbles. However I was quoted over $300 for a single roll which is 10 metres long by 1300mm wide. It would have been enough to wrap all the growbeds but I decided that was too much money. Instead I bought a similar sized roll of sisalation backed fibreglass batting for about $120. This was split into 3 rolls about 400mm wide and then wrapped around each growbed.
The reflective layer is fairly fragile so I then wrapped the beds with the Sisalation I took off the roof when the steel was replaced with polycarbonate.
This also had the benefit of covering over the fibreglass. This should protect the fibreglass from damage and also protect me from the batts which can cause a lot of itching.
We folded the extra Sisalation over the top lip of the growbeds . It is held to the top by a length of split 13mm poly pipe which should keep it all neat. Attaching the poly pipe was not a fun job but if it keeps the whole lot together it will have been worth the effort.

It will be very interesting to see if this part of my plan works as there will still be some heat loss from the tops of the growbeds. The next phase of the construction is the creating of a heating system for the water.

These 2 pictures were taken today. Sharp eyed viewers will notice the beans have gone from the closest growbed during the construction. Peas are the next crop to go in under the wire supports.
We have also pruned a fair bit of the tomato leaves from the plants which are still going well and with a bit of luck they will continue to produce fruit for some time yet.

Plant growth update

2008-04-03T15:10:00.003+11:00

10ft tall tomatoes!!
Well perhaps not quite 10ft but they are much taller than I am even when I am standing on the gravel in the growbeds. In fact some seem to be trying to escape out the window at the top ridge of the shed.
The first picture shows the tomatoes about 6 weeks ago and the second , more recent picture, shows much bushier growth with runners almost to the roof! We have eaten a fair few of the fruit but there are now a bit hard to find in amongst the foliage. I plan to do a fair bit of leaf pruning fairly soon. Early fears that the flowers would not be pollinated don't seem to have come to pass and although not as prolific as I had hoped we are still getting new fruit. With a bit of luck we will continue to get tomatoes from the aquaponics setup for some time yet. In the dirt garden I expect that we are at the end of the season as the frosts are likely very soon.

Despite my earlier comments about lack of nutrients and light the vegetables have been quite productive.
We have had 2 separate batches of tat soi, several of lettuce, and good supplies of peas.
The coriander , in the picture with the beans, was a bit of a flop as it went to seed very quickly- Di reckons it was too hot at the time. Some of the other plantings also went to seed a bit quickly -perhaps for the same reasons. We also had rather slow growth with one of the lettuce varieties and the leaves were bitter so they were pulled out and fed to the chooks
We are currently getting a feed of beans about 2 or 3 times a week from about 30 plants- 10 in each grow bed- some are low as in the picture while the rest are growing on the supports I put in for the peas and tomatoes.
I have not really been a gardener before and so it is quite a thrill to be able to harvest fresh produce whenever I am in the shed.
All I need now is for the fish to produce MORE POO!
This is probably unrealistic now and I will have to wait for the warmer weather to return.

There is however the plan for a hotwater heat exchange unit for the fish- more later!!

An imagined problem and a solution?

2008-04-03T14:48:00.004+11:00

Fish need oxygen to breath just as we do and they get it out of the water. The constant pumping of the water out of the tank and through the growbeds and back into the fish tank provides a lot of air to water contact which ensures the continuous exchange of gases.
It suddenly occurred to me a few weeks ago that if I had a pump failure for whatever reason, and I didn't know about it for some time, I only go over to feed the fish once a day, I could possibly end up with dead fish due to low dissolved oxygen in the water.
This is not really likely to be a problem at the moment due to the small size of the fish but when they are bigger it could be a very real problem. I imagine 200 plate sized fish need a fair bit of water/air contact to prevent them suffocating!
So I went looking for a big air pump- just like the ones used in aquarium setups but bigger.
It had to be at least capable of running on 12 volts and even better 12Volts and 240Volts.
I found one on eBay, bid and won, and a few days later it arrived.
I would not want to have it in a home aquarium setup because it is very large and quite noisy compared to normal aquarium pumps.
However it pumps about 40litres of air a minute and the box contains a 12Volt 7Ah sealed lead acid battery and charging circuitry etc which means that if the power fails it continues to run for some hours on battery power alone. I could also hook up a 12Volt input so that even if my inverter fails I can still keep the fish alive.
At least that is the theory!

Problems and solutions?

2008-04-03T14:22:00.005+11:00

Although growth of the plants in the growbeds is quite vigorous they don't seem to be doing as well as I had expected.
I am reasonably convinced that I have 2 main problems:-
1. not enough light and
2. not enough nutrients.

So in an effort to solve or at lease improve on the light problem I decided to install the extra polycarbonate roofing I had bought at the beginning of the construction.
Taking advantage of a visit from my "nephew" I co-opted Gary into being a roofer's mate and we removed the zincalume roofing over the back part of the shed over the fishtank. This is a reasonably straightforward job despite the difficulty of trying to drive "one-shot" tek screws into polycarbonate sheeting whilst not putting any weight on the sheeting. Fortunately the sheeting is very strong and the occasional accidental step on it doesn't result in a crash through to the ground 4 or 5 meters below.

The fish don't seem to realise that the extra light is good for the whole system and they are currently much more skittish than they were before the extra light became available. I am hoping that they are just getting used to it and will eventually be more willing to be seen.

The not enough nutrients problem is almost certainly due to the fact that I have quite a lot of plants and not enough fish poo! There are probably over 200 fish but the biggest of them are still only about 100mm long- and a lot are much smaller.
So as mentioned in an earlier post I am adding pure Urea at the rate of 4g most days- this has lifted the nitrates to between 10 and 20ppm without causing any detectable ammonia or nitrites.
I was also adding chelated iron at the rate of about 5g per day for a couple of weeks. I was testing for iron in the water but not getting any detectable levels. However I should have been testing for the chelated iron and when I finally did so the levels were between 1 and 2 ppm. This is possibly too high a level so I am no longer adding iron. A test today suggests that the levels are a bit lower and I hope that the plants will take up more. As far as I can tell chelated iron is not toxic to fish and the fish don't seem in any way affected.

The fish are also eating less now due to cooler temperatures.
Temperatures in the shed are now a fair bit lower than they were in the middle of summer- not a surprise- as I write this the temperature outside is only 10 degrees Celcius. The tank was at about 15 degrees earlier today. The insulation I have around the tank is clearly helping to moderate temperature swings.

Unexpected Visitor

2008-04-03T13:50:00.003+11:00

On arriving in the big shed a few days ago I was surprised to see that one of the "fish" was swimming around the perimeter at the surface really quickly.
And then I noticed that there were flashes of red from this "fish".
A closer look quickly showed that it was not a fish but a smallish red bellied black snake! I estimate this one to be about 800mm long.
Clearly it had visited the tank in search of food- The primary food for red bellied black snakes is frogs and other small reptiles.
The big shed is within 20 meters of the big dam and I have often watched red bellies hunting for prey around the edges of the water.
My first thought on seeing the snake was to quickly rescue it as I reckoned it was probably exhausted after who knows how long in the water. I have a small aquarium net taped to the end of a short piece of pipe so this was presented to the snake who immediately swam into it. I took the snake out to the bank of the dam and put it on the ground near the water .

I then realised :-
1. That I had missed a great photo opportunity and
2. That the snake might have eaten some of my fish!

I went back out to see if the snake was still where I had left it and it was- soaking up some warming sunshine. It didn't look like it had a fat belly so I doubt if any fish had been caught. It did look healthy and eventually moved off into longer grass to hide from me.

The fish were a bit skittish for a few days but eventually returned to normal and I although I have no way of counting them it looks as if I still have as many as I had before the visit.
I must come clean and admit that these pictures are not of the snake in this post- I prepared these images earlier. It is one of the snakes which live near the dam which I had photographed some years before.

Top up water

2008-02-06T18:56:00.001+11:00

As the growbeds are not fully planted, and the area is really a glasshouse, a fair bit of water evaporates each day. The growbeds get quite hot to touch in the middle of the day which clearly accentuates the problem. .
To keep the system running well and to ensure the plants get adequate water top up water is needed fairly often- really about every couple of days. The plan is to fill the growbeds to within a couple of centimetres of the top of the gravel each flood cycle.
I have a 20000 litre rainwater tank collecting the water from the shed and I have run a pipe from that tank to just over the fish tank.
Up until the addition of the top up barrel I simply opened the big white gate valve and ran in water for a short while. The problem with that arrangement was that I didn't know how much water I was adding and more importantly on one occasion I forgot the water was running for about 10 minutes and ended up adding far too much. I didn't overflow the fish tank but I did have to reset the float switch which was a pain.
So I have added a 200 litre blue barrel which has a sight tube which enables me to add, and record, an accurate volume of water when needed. At this stage it looks like I need 50 litres every second day. I doubt that I will need to add anything like this much in the cooler months but it is still likely that the extra water needed over a year could be as much as 7000 to 9000 litres. We have had a fairly wet last couple of months and the 20000 litre tank is still full so that much water will not be problem. Posts to several of the online aquaponics groups suggest that an aquaponics setup uses only about 10% of the water of a dirt garden. I have no idea if that is true but I do know that we had real trouble with enough water for our dirt garden the last couple of years wheras we look like having no trouble with water with this new venture.

Azolla production

2008-02-06T18:15:00.000+11:00

I have been reading all sorts of good things about the food value, for fish, of the water fern azolla. It contains quite a lot of protein in the dried state and has been used in lots of places around the world as a protein supplement in livestock production. The most interesting thing about azolla is that it can double its mass every few days when provided with the right conditions. I had a few failures in trying to get a culture going but am now producing quite respectable quantities on a daily basis. This is scooped out of the pond and dried on a rack which is simply flyscreen over a bit of steel mesh. After a day or so of drying I rub it through a sieve and now have about 9 or 10 litres of dried leaf. As the water content of the living plant is about 95% the 10 litres of dried leaf represents probably 200 litres of fresh azolla. And that was all produced in the 1200 litre stock trough outside the shed over about a month or so. This little plant grows like a weed when given the right conditions.
To start the culture the trough was half filled with water and a couple of biscuits of hay and a handful of super phosphate was added. This creates an algal bloom which was actually planned as a starter food source for mosquito wrigglers and daphnia. I got quite a few feeds of wrigglers and daphnia for the fish but then in a moment of weakness chucked in a few handfuls of azolla. The water in the trough became so covered with azolla that I no longer get a harvest of live food for the fish.

So I have now created a new area where I can grow azolla and this will free up the big trough for live food production. The dried leaf will become one of the ingredients of my homemade fish food - more about that later.

The new area is made up of 6 half blue barrels each of 100 litres - the total volume is about 600 litres and the total surface area is about 3 square metres. These have been seeded with hay and/or super and should be going green within a few days . I plan to start adding chicken litter and droppings in the new areas as an experiment. The overall plan is for as many of the inputs to the system to be home grown- sort of a permaculture system where one areas waste is another areas nutrient.

The pieces of shadecloth in the water are there to give lizards, which seem to want to get into the barrels all the time, something to climb out on. Before the shadecloth went in I inadvertently trapped several of the Cunninghams skinks which live near the shed. Fortunately the water was not deep enough at the time to drown them and they survived.

More fish

2008-02-06T17:48:00.000+11:00

A couple of days ago I received a delivery of 100 Silver Perch fingerlings . These were part of the original plan but were not available until last week.
They came from
Ian Charles at
Silverwater Native Fish , Old Wagga Rd, Grong Grong NSW 2652 ph (02) 69562122.

A really nice bloke to deal with. I had a chat with him as he was delivering live plate size Silver perch to a Chinese restaurant in Jamison. He transports the big fish in a heavily insulated box with a pure oxygen bubbler. The fish are partially anaesthetised by adding a small amount of clove oil to the water. He had about 90 fish weighing between 600g and 1 kilo in a 400litre box- all quite happy - but very crowded.

My fish were a lot smaller- between 40mm and 80mm. Unfortunately about 20 died in the first couple of days but the deaths have stopped and the fish now look fat and healthy.
They spend most of their time in the middle water unlike the cats which are mostly on the bottom. Like the cats they are very fond of chopped earthworms and when feeding seem to encourage the cats to move higher up in the water. The cats will have to eat faster if they are to get their share of the worms. Worms are a treat- the primary food at this stage is a sinking pellet food which although Australian made is made from imported fish meal so I plan on making my own fish food in the not to distant future.
I suspect that the silvers will grow a fair bit faster than the cats so we might be having fish dinners late this year with a bit of luck.

A progress report Jan 08

2008-01-13T15:14:00.000+11:00

It is now mid January 2008 and the system is working well.
We have had quite a few feeds of sugar snap peas, Tat soi, lettuce and pakchoi.
In fact the first crop of tat soi has all been consumed and a second crop is now on the way as you can see from the picture on the right. The sugar snap peas don't look great but they are still producing a few pods. We will soon be cutting off the plants- planning to leave the roots in the gravel so that they will release the fixed nitrogen back into the system.
Having a little bit of leaf eating grub problems- probably the white cabbage moth- not a major problem yet so I don't think we need to do anything drastic. Any grubs I see will become fish food and that is really just extra protein.

The fish are growing a bit slower than I had expected- now perhaps 60-80mm long and looking very healthy. I have even worked out how to catch some for photo sessions. Used a yabby trap which was simply left on the bottom for a day or so for the fish to become accustomed to it . I then dropped what has become a preferred food- chopped earthworms- into the trap which I lifted quickly out of the water. Caught about 20 or so very vigorous little catties. They now look more like fish than tadpoles. Not hard to see why they are called catfish with those whiskers!

I had thought that I might have had a problem with nitrate levels and this has turned out to be the case. However I was a bit worried that the levels would be too high whereas in fact the level had dropped to almost nil. This would not be a problem if I had a population of large fish. However my fish are very small and the growbeds are quite large and so the fish poo seems to be unable to keep up with the plant's demand for Nitrogen. So I have started adding extra Nitrogen in the form of urea. I bought a box of pure urea from a garden supply centre and have begun to add 4g per day to the fish tank. Apparently fish don't produce urea as most other animals do when they need to excrete Nitrogen. Fish produce ammonia. Fortunately it looks like urea is much less toxic to fish than ammonia and so far this seems to be the case with my fish. I decided on 4 g per day on the basis of it being 1 ppm for the 4000 litres of water. I am assuming the biofilm is converting the urea to ammonia which is then being converted to nitrite and nitrates in the usual way. After a week of adding 4g per day I now have lifted the nitrate level back to about 10ppm while the ammonia level is still Nil.

Despite the potentially low Nitrogen levels the tomatoes planted in November have finally flowered and have begun to set fruit. Still only the size of marbles but I reckon the extra N will get them away and we should be able to start picking tomatoes within a couple of weeks.
This is very exciting as the original plan really was to ensure a tomato crop after the problems we have had in the last couple of drought years in the dirt gardens.
The last picture shows the dozen or so tomato plants. Note the runts on the left of the picture. These were moved just after germination and this was clearly not a good idea. We successfully transplanted tat soi plants but it was probably too much strain for the tomatoes. I will leave the runts in the growbed just to see what happens.
With a bit of luck we might get a late crop.

Veggie production- Tat soi

2007-11-30T12:18:00.001+11:00

The fish production in these systems is almost a side product as it will take at least 9 months to produce fish of edible size.
In the mean time we expect to get many kilos of veggies.
The system has only been running for a little over 2 months and already we have eaten a fair few lettuce, pak choi and tat soi plants.
The first seeds actually went in before we got the fish as the system had cycled and there was enough nitrate in the water to support plant growth.
The total growbed area might actually be smaller that optimal for the size of the fish tank- If I find that the nitrates in the water build up to too high a level, (no real idea what that would be at this stage), I will probably add more azolla or duckweed to the fish tank and/or do a partial water change.
We decided not to grow or buy seedlings elsewhere but to simply sprinkle some seeds directly onto the growbed gravel. This seems to work really well- in fact a bit too well as we have had to do quite a bit of thinning once the seeds germinate.
The first picture shows tatsoi about a week after planting and the second shows the same plants after we have eaten the majority of those left in the initial clump and now about to harvest those which were transplanted from the original crowded area. Transplanting set the seedlings back about a week but in effect spread the useful growing season out by an extra week or two. The first picture was taken on 1st October 07 and the second on the 25th November 07 ie total time from planting to almost final crop about 8 weeks. We planted a new lot of seeds about a week ago so should have another harvest of tat soi in about a month.
In the background of the second picture you can see flame lettuce- this was planted about the same time as the initial tat soi but is very congested and probably needs a lot of thinning for individual plants to get away.

Fish

2007-11-27T18:06:00.000+11:00

The choice of initial fish was partly determined by what was available and by what species could survive the expected lower temperatures we get here in wintertime.
While I was waiting for the weather to warm up I placed a recording max min thermometer in the fish tank and recorded reasonably stable temperatures in the water. However the low point of 7.5 degrees Celsius means that most of the fish I thought I would like to keep would not be viable.
Help from the Backyard aquaponics forum lead me to decide on Tandanus tandanus ( the Australian eel-tailed catfish) and Bidyanus bidyanus (Australian silver perch).
I remember eating catfish years ago and being very impressed with both flavour and texture so that was a happy discovery. Silver perch is considered one of the really successful species to grow- very hardy and also very good eating.
I managed to find a source of supply for the catfish and so went to the Murray Cod Hatchery at Gumly Gumly , near Wagga,
Murray Cod Hatcheries
RMB 626 Sturt Hwy Wagga Wagga NSW 2650
ph: (02) 6922 7360
and bought 180 fingerlings. They were about 40 to 50mm long at the time. Greg , the owner of the hatchery will possibly have silver perch late this year and if so I plan on buying about 100 little ones then. Greg also reckons they will live quite happily with the catfish without either species wanting to eat the other.

The fish were floated in the tank in the usual way and then when tipped into the water they simply disappeared as the water was so muddy.
This was cause for some concern as I was worried that I couldn't see the fish and so had no idea if they were feeding or not. By the time the water cleared enough for me to see the bottom I was a bit distressed to see a couple of bodies there. I fished out about 10 or 12 dead ones over the next couple of days. I have also removed a couple more since. It is almost impossible to estimate what my actual losses were as the fish are still quite small and difficult to see. Some have grown quite significantly however and there is quite a range of sizes. A few are about four times the body mass of the smallest. I expect uneven growth and it is actually a benefit as it would be a bit of a problem to have all ready for eating at the same time.
At this stage they are feeding on 2.5-3mm sinking pellets for Australian Native fish as the main diet with supplements of live Daphnia and mosquito wrigglers when I can catch the same.

The pictures were taken when the water was muddy and I managed to catch a few who were silly enough to come to the surface. I am no longer able to catch them as they can see the net coming and escape like little rockets.
They look a lot like tadpoles and swim like tadpoles as well.

Initial nitrogen cycle

2007-11-27T17:37:00.000+11:00

For the system to work properly it is necessary to establish the bacterial film which will convert the fish waste into something which the plants can utilise.
This film will grow primarily on the surface of the gravel in the growbeds and would have happened naturally without intervention from me. However I wanted this to happen as soon as possible so I took a big sponge filter out of a filter in another fish pond I have and rinsed it out in the water in the big 4000 litre tank. I then got some dead fish we had in the freezer ( flathead fillets and squid which had been forgotten) and suspended this in a couple of nylon bags in the fish tank water for about 3 weeks. I also bought a comprehensive test kit so that I could monitor the progress of the establishment of the cycle.
Unfortunately I clearly missed the peaking of the ammonia production and so don't know how long that took to happen. By the time I got around to testing for all Ammonia , Nitrite and Nitrate the levels of the first two were basically trace to nil. Nitrate was quite high and has remained so ever since. This is not bad as the system had clearly cycled and all ammonia is being converted to nitrate before it has a chance to hurt the fish.

Aquaponics- what does it mean?

2007-11-27T17:25:00.001+11:00

The word is a combination of Aquaculture and Hydroponics.
Basically it is the setting up of a self contained system which uses fish to produce nutrients for bacteria which convert ammonia compounds into nitrites and then nitrates which are taken up by plants which in turn purifies the water and make concentrations of fish which would not otherwise be possible.
If all goes according to plan I should be able to raise at least 100kg of fish per year in 4000 litres of water. That is 2.5kg of fish per 100 litres of water which is actually a fairly conservative stocking rate.
Needless to say the system needs to be carefully balanced and that is the real trick. If any part of the scheme fails the whole thing will fall over and neither fish nor plants will thrive and/or survive.
Versions of aquaponics have been in use for thousands of years so it is nothing new.

Shed Modifications

2007-11-27T17:02:00.000+11:00

The shed is a 15 metres long , 9 metres deep and about 4 metres high and is my main storage area for machinery and general junk.
The western end already had a couple of tray of translucent polycarbonate in the roof but that would clearly not let in enough light for plant growth. So with help from my brother inlaw Jack we cut out part of the northern and western metal wall cladding and replaced it with Laserlite sheeting (another polycarbonate product). That didn't seem to let in enough light either so the steel sheeted roof area over the growbeds was also replaced with Laserlite.
Just in case this lets in too much light in mid summer I made a retractable blind from 70% shadecloth and attached it to the roof joists so that if needed I can partially shade the area in the hottest part of the day. At this time of year the blind is folded out of the light.
I am still not sure if we are getting enough light onto the plants and I have some more Laserlite to convert more of the roof if needed.
The shed has 3 large roller doors and small louvre windows in the apex of the roof at each end so I hope that we will get enough air flow to prevent overheating in the summer.
I have taken to opening at least one of the roller doors when I feed the fish first thing in the morning and closing the door after the last feeding at night. The vague theory is that this way I am getting airflow and reducing the risk of fungus due to high humidity and still air. Time will tell if this theory is valid. I am assuming that the height of the growbeds off the ground will keep rats, rabbits and those big rabbits (Kangaroos) away from the lovely lush green stuff.
I also have a plan to make big hanging curtains, with shadecloth, for the door openings if needed to keep out grasshoppers if they become a problem later in the summer.

Power

2007-11-27T16:37:00.000+11:00

The pumps are 240V AC and this is supplied via an inverter over the battery bank which takes 12v DC and changes it into 240v AC. (The inverter is not shown in the picture as I didn't have it when that pic was taken).

I decided to use 240V AC for a couple of reasons:-

1. I had already bought an inverter (on e-Bay) so that I could use 240V AC tools in the shed which is not directly connected to the house power supply. The shed contains a battery bank which was a cast off from the house some years ago and which is kept topped up by two 80watt Solarex PV Panels on the shed roof. The bank is twenty four 2Volt 560Ah batteries each of which weighs about 50kg. These batteries came out of a Telstra phone exchange and were part of a batch which included a bunch of duds- so I had to replace all them with new ones for the house supply- another saga in the life of an alternative energy enthusiast.

2. It has been difficult to find quality 12V sump/bilge pumps.

I have wired in a 240V AC outlet near the fish tank and this has the remote float switch plugged into it. This float switch bypasses the float switch on the new pump. The float switch is attached to a pole in the water and the levels at which the pump switches on and off are adjusted by changing the length of the tether on the float and the position of the ties on the pole.
It looks like the total power usage per day exceeds that generated by the panels so I have run a 240V line from the nearby pump house and have plugged a small battery charger into that line. This now trickle charges the battery bank and seems to be keeping up with the demand of the pump. The new pump should reduce the drain on the batteries significantly.
The pumping cycle now is pump on for about 8 minutes and then off for about 56 minutes. This gives about 22 cycles a day. Each cycle pumps about 750-800 litres a time so the total tank content is cycled through the growbeds about 4 to 5 times a day. In fact it is actually a bit more than that because the water is returning to the tank at the same time as the pump is moving it out. A quick experiment today suggests that the pump is actually moving about 10-15% more water with each cycle.

Plumbing

2007-11-27T13:57:00.000+11:00

As you can see in some of the earlier pictures the plumbing is in 2 sections.
1. The water from the fish tank to the growbeds and
2. Return water to the fishtank.
The first bit is via a big sump pump which is on the bottom of the fish tank and is connected to the growbeds with 1 and a half inch (40mm) black agricultural polypipe. This is used because I had lots of the poly bits in stock as it is the same pipe we use for all the outdoor plumbing between dams, the bore and header tanks etc. The pump is in a filter sort of bag I had to make to prevent the fish from being sucked into the pump and mulched. Not a happy thought.
The return is via gravity and 90mm stormwater pipe.
The water was very muddy initially so I made a filter from a mop bucket with many holes in the bottom and about 15-20 layers of quilting batting from spotlight. This has taken most of the mud out over time. It also probably increases the aeration of the water which is a plus.

Each growbed has a gate valve on the input so that I can adjust the flows to even out the fill levels to individual growbeds. This took a fair while to fine tune and would have taken forever if I had used ball valves instead of "John valves". Each valve now has a cable tie to prevent accidental changes to the settings.
As the whole system runs on solar charged batteries it is very important to me that the pump is as efficient as possible.
So the gate valves are set so that the last growbed has a fully open valve and the others are closed just enough to ensure that they all fill at the same time.
The first pump is a big blue unit which is rated to pump about 15000 litres an hour to a head of about 2 metres using about 700 watts of power to do so.
The current pump uses only 250 watts to pump a rated 8-9000 litres an hour and actually only takes about a third longer to pump the same amount of water as the big one. This suggests to me that the big one is actually throttled back by friction in the delivery pipes. This came as a bit of a surprise as I thought short pipe runs and 40mm fittings would not be a real restriction.

Once the water gets to the growbeds it is distributed via a series of 25mm pipes with lots of holes in the bottom surface. This prevents water spray and hence evaporation and also limits algae growth on the top of the gravel. The return water from the beds is restricted by bits of 40mm PVC with just 2x 6mm holes in the lower section. This was just luck and means the return takes about an hour before the pump kicks in again.

Growbed construction

2007-11-27T13:24:00.000+11:00

The growbeds are 1200l teampoly stock water troughs. They are about 2 metres in diameter and 400mm high.
These were chosen as similar to those used by Joel Malcolm. However I couldn't get a reasonable price for custom made steel troughs/tanks so I decided to buy poly ones. Poly will also not rust and is fairly easy to work with.
In retrospect I feel that round grow beds are not a good idea as they are hard to arrange in a limited space (I could only get 3 of the 4 I bought into the available space in the shed) and stands are complicated to build for a circular shape. AND it took 4 months for the manufacturer to complete the order!
The stands were complicated as the pictures show however they easily support the weight of gravel and water when full- estimated weight is probably over 2 tonnes per growbed when full.
I have put a layer of 19mm yellow tongue chipboard over the base then 25mm of polystyrene sheeting. I plan to also wrap the walls with polycell or aircell blanket material when we get closer to winter next year.
The stands were set on bricks so that they had a slight fall to the planned drain plug area and the drain holes cut unto the base. A normal laundry drain fitting was then screwed into place with a fair bit of silicon to ensure a waterproof join. Details will appear in the plumbing post.
The growbeds were then filled with gravel- Bungendore 10mm brown- selected for its smooth feel and average stone size of about 10mm. Really I just went to a sand and gravel place and handled all the potential media and selected one which felt comfortable to touch. Some people use blue metal but it felt to sharp to me.
Before the gravel went into the growbeds I had to decide if I should wash it. I did wash one cement mixer full but decided it would take too much water and also too much time. So unwashed it is. I thought that the flood and drain cycle would eventually wash out most of the silt etc. And it has although it took much longer than I expected. The system has been running now for just over 2 months and we can only now clearly see the fish on the bottom.
I feel that the silt and mud which is still visible in the growbeds will probably be good for the plants in the long term anyway so it was probably the right way to go. The only real problem was that I couldn't see the fish for the first couple of weeks and it is hard to know how they are going when they are not visible.

Initial construction - fish tank

2007-11-26T14:23:00.000+11:00

It gets too cold here in the wintertime to maintain the fish I wanted to keep so I really need to build a super insulated glasshouse for this project . However I couldn't decide on how to do this despite many versions of plans in my head.
So I decided to modify one end of my big shed to accomodate a trial setup- ended up a bit big for a trial but I think it will work well enough to determine if the construction of a dedicated greenhouse will be worth the effort.
Without really giving the whole thing too much thought I decided to simply copy what has been show to work by Joel Malcolm in Perth. His system is outside but apart from that minor detail my system is fairly similar.
As stated elsewhere we are entirely solar powered (actually partly wind powered but that is really a small part of the total) and so the system had to be as energy efficient as possible.
So the tank and grow beds are, or will be, heavily insulated to conserve as much heat in the winter as possible.
I also had to minimise pump usage so the system is a flood and drain one where the pump runs for between 6 and 9 minutes in the hour and drains back via gravity. IE no sump pump.
I have recently changed the pump but I will leave the details of that to a separate post.
So the fish tank had to be below the level of the growbeds if a gravity system was going to work. It also needs to be well insulated so one really big hole was needed- 2500mm across and 1400mm deep.
Took me 4 days to dig the hole . Basically dug by hand- needed the jackhammer to break up the dirt and used the tractor bucket to move it outside. Not sorry to have finished that little job!
Then put 20-30mm of crusher dust in the bottom , leveled it off and added 25mm of expanded polystyrene over the bottom. Lowered the tank in, packed 30mm of expanded polystyrene around the edge and backfilled with more crusher dust.
The tank was then filled with water and left to sit while I tried to work out some way of heating the water. This part of the plan is still in thought/planning stage as the initial plans were thwarted by the fact that copper pipe in contact with the fish water releases copper which can be very bad for the fish. Continuing cold weather basically put the whole scheme on hold until it started to warm up in September.

First post and links to my threads elsewhere

2007-11-20T11:20:00.000+11:00

A new blog just for the fun of it so that I can show off my latest passion.
Actually this is a reignited passion as I used to have LOTS of fish tanks when we lived in town.
Now live in the bush and have lots of room to indulge in experimental things.
Because we are entirely solar powered, in the grip of a fairly severe drought and always want to have as small a carbon footprint as possible the concept of Aquaponics has huge appeal.

It all started with an article in Organic Gardener (ing?) about this bloke, called Joel Malcolm, in Perth who apparently grew 60kg of Barramundi and several hundred kilograms of veggies in his backyard. I bought his excellent book , read it cover to cover several times, and started building a similar system.
Check out his web site:-
http://www.backyardaquaponics.com/
and the associated forum
http://www.backyardaquaponics.com/forum/
All sorts of good stuff to be found there. A bit of chaff to wade through sometimes but also a lot of really great informantion.
I have a thread here :-
http://www.backyardaquaponics.com/forum/viewtopic.php?t=1431&highlight=
Another useful site is
http://www.aquaponicshq.com/forums/index.php
my thread is
http://www.aquaponicshq.com/forums/showthread.php?t=17
This one doesn't have as much activity and a lot less chatter but also some really useful info.
Both site are Australian based so most of the info applies to us.

Part of my justification for this blog is that I post to both sites on an irregular basis and this might enable me to keep a more current series of progress pics and thoughts.
The posters on both forums(?) are usually a lots further advanced that I am and probably aren't going to be as excited as I was today to discover that my catfish really love mosquito wrigglers for example.

You might have gathered from the somewhat disjointed waffle above that this blog will be a somewhat haphazard affair- but isn't that what blogs are for?? More later.