A tip for extra long bell siphon drain pipes

[Ryan Garlington]

This took a while for me to figure out, and I thought Id share it in case anyone has a similar situation.

I had to add my second grow bed pretty far from my fish tank and run 20 feet of pipe around a shed to get the pump and drain pipes connected. I tried every adjustment I knew to get the siphon working right, but it would never stop draining. I finally realized that there is no way that the air above the water flow in 20 feet of pipe could go all the way back to the siphon and break the flow.

The solution is a vertical air vent pipe- almost like a venturi, but with no rubber tubing added. I put this pipe about 2 ft down the drain pipe and now the siphon can make that gargling slurp sound, then stop draining. Water wont come out of the top since the tip is higher than the maximum water line of the grow bed.