I'm new to all this, kind of a learn as I go. Maybe not the best way of doing it...that being said. I have a GB that is 3.5 ft. x 10 ft. @ 14 inches. I have tried lot of different bell siphon designs. 1st one was a 4" Media blocker, 2" bell, 1" stand pipe with a 3/4" reducer at the bottom of the stand pipe. The 2nd one was a 6", 3" bell, 1 1/2" stand with a 3/4" reducer. Here is where I think I went wrong, All this connected to a 1" drain pipe, I used a 90 with a 20" long PVA then another 90 (this make a long pee trap). At that point I used a 90 to head to my Fish Tank with about 5 ft. of PVA at a slight downward angle. My G.B. is made out of block with 2" of cement on the bottom of it covered with a pond liner. All buried in the ground, my 1,280 gal Fish Tank is made the same way & is 7' x 7' @ 42" deep. The bottom water level of the G.B. is about 10" above the high water level of my tank.

Nice to find you guys, my girlfriend told me about you months age. I should have taken the time to do more research though this site. Would of, could of, save me a lot of time!