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Thread: My backyard aquaponics system
06-17-2009, 04:38 PM #1
My backyard aquaponics system
I finally got some shots from my backyard aquaponics system together!
It is a fluidized gravel bed system with approximately 140 gallons (530 liter) water volume with 60 gallons (230 liters) of 3/8" (.95 cm) pea gravel for media.
The rearing tank is a 110 gallon oval stock tank with a center bottom drain. It currently houses 6 shubunkin goldfish and 1 coy.
The center bottom drain is fitted with an elbow and piped horizintally into a plastic barrel. This barrel houses two pumps and bio-balls and is areated with a pond air pump. The small areation pump constantly runs and leads back to the top of the rearing tank. It has an elbow to give the large tank a slow clockwise rotation. The larger pump is controlled by a timer and floods the Grow bed through a PVC distribution network.
My grow bed is wood framed with a PVC pond liner. It is 4'x4'x8" deep, and is based on the square foot gardening method from Mel Bartholomew. Each of the (16) 1' squares is fed from two sides by the distribution network. The bed takes about 1 minute to fill to the top, activating the two auto siphon drains bulkheaded (ghetto stye) to the front of the growbed. They suck the grow bed down to about 1" of water in less than a minute. The rapid draining action is important because it creates suction and draws oxygen down into the gravel.
At about 1", there is less pressure pushing on the siphons and they reach equilibrium with the pump. The water is still running, but it is acting like a trickle system now. When the pump turns off, the siphons will break leaving about 1/2" in the bottom of the bed. There is about 2" of course lava rock under the gravel to improve flow. The siphons drains create a rapid counter-clockwise vortex in the rearing tank. Pump times are 5 to 15 minutes depending on the time of day. The pump runs every two hours by day, four hours by night with a 6 hour rest period from midnight to 6am.
Current water parameters
Total Ammonia .5ppm
Biggest problem right now is temperature stability. I plan to insulate both the rearing tank and the pump tank.
Next biggest problem. Spider mites!! I plan to spray the plants with a capsicum and garlic solution and try not to get it in the water directly! I have to admit that my bio-security sucks in this setup. I sooo wish I had a greenhouse, but you gotta start somewhere!!