My SO and I decided to create a small DIY cheap-as-possible aquaponics project. She was inspired by the Kapiolani Community College garden, which has a pretty significant aquaponics system.
I have no experience with gardening, other than growing a few tomatos and herbs at my parents house. My SO has much more knowledge in that area. I do however, understand the basic concept of an aquaponics system(thanks to Google), and basic knowledge of a bell siphon, which I'll go over in a bit.
With the design left to me, we headed to Home Depot for supplies. We picked up two small plastic bins, one being almost twice as large as the other. We wanted to go with a 1:2 ratio of grow bed to fish tank. We also grabbed 15ft of white 1/2" PVC, a valve, a 1" to 1/2" adapter for the bell siphon, 1ft of 3" PVC for the shield, and numerous fittings such as a 90 degree, 3 way splitter, and 45 degree. For the grow bed we use a charcoal type grow media that was suggested to us from our local hydro/aquaponics store. We also picked up a small pump from them.
My first idea was to have the pump move water over the grow bed and empty it through holes in the pvc pipe, and at the end have it circulate back into the fish tank. Seen below:
This however, wouldn't work because I wasn't able to control the flow into the bed. So I decided to go with a 3 way splitter to control the pressure of the pipe carrying the water up to the bed. The released water pressure would go back into the fish tank, while also aerating it for the fish. This seems to be pretty common in aquaponic systems. Shown below is the updated version.
For the bell siphon design, I use a 1/2" to 1" PVC adapter. This provides enough high pressure inside the pvc pipe to cause the siphon to start. For the bell part of the siphon, I use a starbucks glass bottle. Why do I use a starbucks bottle as the bell? It fits perfectly, and it being transparent helps me diagnose problems with the siphon, such as clogs. It was also free. To allow water to flow under the bell and into the top of the siphon, I have a loose zip tie sitting at the bottom that keeps the bottle off the floor.
To be continued in part 2, where all our fish die, upgraded parts, and a new design.