Monday, January 19, 2009

Fish finally growing


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.