Faye from another thread suggested i post a new one here:
Tyres for Tanks- Fish Air-conditioner/ This is my homebuilt system. Its a year old now and so far no major malfunctions, no leaks, good plant and fish growth.The picture below is 6 months old after pulling out initial tomatoes & cucumbers and replacing with water plants. Ill post a current comparison pic shortly to see how plants have grown. Im cautiously optimistic about aquaponics from my limited experience. Ill admit it is working a lot better than i expected. I started out with moderate expectations, which i guess helped here. Ive opted to focus on growing water plants in the growbeds rather than vegetables because I was primarily interested in the fish and the design benefits of using water as part of energy efficient architecture especially its application to retrofitting existing houses/yards . In less jargon.......My aquaponics system is essentially an extra water feature in the shadehouse as part of passive cooling arrangement for my house. Most backyard systems seem to be fish tanks that grow veges whereas for mine, the focus was more to be an
air-conditioner that grows fish. I have 'wick' system garden beds for the veges which can use the fish water that comes off when i syphon clean bottom of tanks, but they use good old soil and horse manure too.
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The Tank
-2 large diameter cloth radial (for easy cutting out of wall) agricultural tyres
-They are header/chaser bin tyres, dont ask me exact numbers or dimensions. They make a tank with about 2000L capacity.
-Wall is cut out of one side starting about 2 - 3 inches from edge. Only cut to make the tank opening the minimal size for a couple of reasons:
1) keeping rigidity in tyre. Top edge of tank nice and firm/solid supportive for kids jumping up all over it leaning on it to view fish.
2) keeping the light entry to tank to minimum. The curved sides of the tyre are the other big advantage here. Maximum volume water/minimum light entry into tank, yet still open enough to see/feed fish. Combined with the shading from the grow beds, i seem to have no problems with algae. Admittedly the old setup is under shadecloth.
-Lined with silage/grain bag heavy duty PVC. This tough useful material is virtually a waste material in the grain growing regions (believe it or not) a lot of it is buried or burned or left flapping around in the wind. I think recycling schemes have started, but it is non-reusable after being used as a grain bag and is discarded. Find a grain cocky with the stuff and he/she'll be happy to give it away.
-Try and get hold of the liner before it flaps around the farm for 10 months so reducing the likelyhood of crease faults, pin holes etc.
-I used 2 layers just in case i did have any tiny holes.
-Set up your tyre in its desired position. I first placed a square of conveyer belt on ground where open side of tyre will lay, so when you put your plastic in its all plastic/rubber contact. Level it, make sure there is nothing sharp on insides. I washed mine and inspected carefully, run your hand all over inside. Take time and care with the preparation. This is easy, quick and pretty cheap but one small hole caused by a tiny shard of gravel you accidentally kicked in there because you were rushing the job, a hole in the plastic and you might have to start all over again.
-The plastic is simply laid over top of tank then put hose in middle and start filling (dont forget to properly level your tyre first). As the water pushes the middle in guide the plastic down with your hands. The weight of the water will gradually push the plastic layers into the walls of tyre.
-when working out the size of the squares of PVC, measure what you think will be plenty big enough......then double it. You'll be surprised how much you lose in the folds. Don't even try folding the plastic to fit in tyre unless you are an origami genius or feel like a geometry challenge. Either way, good luck when you've finally done it 24 hours later. The fish wont notice or care.
-Once tank is full, secure your plastic liner by making a band around tyre you can tighten. I used some no 8. soft wire threaded through some old garden hose then tightened with a gripple. For those not familiar, a gripple is a little self ratcheting joining device for fence wire you thread the two ends into. Need the tighting tool to pull the band tight around tyre. Again find a farmer and borrow.
The Growbeds, tankstand, syphon setup
-50L plastic tubs, bell syphons in each all made from scrap PVC pipe
-Scoria for medium. Light, relatively cheap if buy bulk. A ute load will disappear quickly.
-Suspended by frame made from inch gal pipe
-Key advantage of a tyre tank is its ideal height. Its a good working height to see, feed fish.
doesn't make grow beds too high. The height from bottom of tank to surface not too deep so your airstone will be more likely to still work when its on bottom of tank. As stated before, curved sides enable good visibility into tank whilst not allowing too much light into water volume.
-PVC
elbow fittings for syphon drains on bottom of grow beds seem to do 2 advantageous things. 1) They seem to create some additional friction to hold water up in syphon better so the syphon 'trips' easier. 2) better water splash back into tank - more aeration
Aeration + water pumps
-Nothing really new or enlightening i don't think to add that isnt said elsewhere.
Maybe just a couple observations.
-Can substantially improve airflow by pushing your air down larger diameter pipe. A no brainer but worth mentioning. I have a small 7 watt standard aquarium airpump, cost about $30, putting plenty of air into 2 * 2000 litre tanks that are a combined distance of about 12 metres from pump. I made 2 adapters out of plastic garden irrigation fittings (a 9mm end plug and small tube joiner, use soldering iron) to bring the small tubing from the pump up to 9mm dripper pipe the reduce back when at tank to airstone. Can put pics up of this on request.
Fish & Feed
-50 Silver perch in one (15 - 20 cm long)
-130 SP in other tank, 5 cm
-Am I understocked for 4000L ???? I dont know, not an expert. Since im growing mostly water plants adapted to lower nutrient demand, im not overly concerned if understocked.
-Ive been experimenting with different 'dough mixtures' made from various grinds of grains, sprouted grains and eggs.
-Best one seems to be blended lupin sprouts, lupin flour mixed with egg, kneeded with plain flour
weaned onto this feed firstly by flavouring the dough with ground commercial fish feed pellet. The silvers literally fight over the balls of dough when i drop into tank. Growth rate seems to be high. Ive only been doing this new feed for 2 weeks so please DONT try it at home yet!! so far nothings died, but id like to trial this feed for a bit longer and do some more research before im confident its not bad for the fish. So far so good. I grow the lupins and eggs on farm. They get earthworms too from the worm farms. I do throw shredded lettuce in occasionally but i don't know if they eat it or not.
Thats about it. Im new to the world of aquaponics forum so i promise all my posts from now will be short and sweet. This is basicly to intro. my self and sytem for any questions comments, ideas.
Graham.
Backyard Aquaponics
