Aquaponics: is the symbiotic cultivation of plants and aquatic animals in a recirculating environment. Alternate definition: An integrated hydroponics (growing plants in water) and aquaculture (growing fish) system. http://en.wikipedia.org/wiki/Aquaponics
Aquaponic systems can be small like this one or large commercial setups. I have found http://www.aquaponicshq.com and invaluable source of information.
This system is very simple. Basically I put a box on top of my fish tank and pushed the pump through it and added some holes rocks and plants.
Step 1: The Grow Bed
In this example I have used an old plastic storage box. I drilled two large holes on one side.
1 For the Pump to go through
1 as an over flow valve in case drain holes fail.
Along the one side I drilled a series of holes to drain the water back to the tank.
Then simply placed the container on top of the tank at an angle to allow the drain holes to be flow back into tank and the pump and over flow to be near the top. (Look at side view)
The pump I am using is the standard pump that came with the tank. Any pump will do just needs to pump water from tank to the grow bed.
After washing the grow medium I place it in the grow bed.
Now I let the system run to ensure it doesn't over flow and look for any issues.
Step 2: Plants
In this case I planted some Lettuce along the top (Close together but will thin out latter) and some watermelon seeds along the bottom.
Plants will grow quickly in aquaponic systems.
The plants clean the water for the fish and the fish dirty the water for the plants. What a great cycle :-) The chemistry of it can be found on almost all Aquaponics web sites so type the word into google ( http://www.google.com.au/search?hl=en&q=aquaponics&btnG=Google+Search&meta= ) and learn more. This would be a fun Classroom experiment and an example of natural cycles.
Step 3: Fish
Other aquaponic systems have anything from Yabbies (small fresh water crustatian) to large eating fish I have even heard of a salt water systems.
Step 4: Completed
My pump stops pumping once it is exposed to the air and since it is just below the water surface if a block does occur it wont result in much water on the carpet. I would suggest you think about the possibility of an over flow.
I will report back on the growth of the plant in this system.