DIY U Tube Overflow questions

[MarinePaethor]

I have read quite a few posts around the net about building a u tube overflow out of PVC. Since I am currently on a fairly tight budget, I think this is the direction I want to go. I have a few questions about flow rate though for anyone who has any experience building and using this type of overflow.

I have a 46 gallon tank, and am looking at a 630gph return pump. With a 4' return to the top of the tank, and 2 elbows at the top to get the return back into the tank, I am looking at around 400gph return from the sump. What size PVC should I use for the u tube overflow? If I stepped up to a pump that netted me around 700gph return, what size PVC should I use?

Does anyone have any tips or tricks for building a U tube overflow that they figured out to make it easier to use or more efficient?


Thank you very much for any answers or suggestions you can give me on this.

[waqas_01]

I started off with the pvc overflow for my 55 gallon aquarium but i could not get it to keep a siphon. I think the problem was that i had my drain line underwater in my sump so a complete siphon would form and suck the pipes dry. Just be ready to spend some time on it to get it working properly. As for flow rates, I'm not too sure, I was running a 650 gph pump that was throttled down and then there was also head loss also.

A better option would be to drill your tank if you haven't already started it, or a hang on back u-tube overflow. The other type of overflow is the cpr type but they need a aqualifter pump to keep them primed. Just another thing that can go wrong. I'm running a u-tube overflow for about 9 months now without a problem. Just regular maintenance.

Hope this helps.