The end of the experiment

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??

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.