Drain size

[jason77777]

Im designing a new drain system for a saltwater 150 gallon dual corner overflow. Both have 1" bulkheads. I'm running 2 780 (at 0' of head, return pumps so more like high 400s) I was planning on using 1" PVC to plumb the drains back into the sump. Research tells me I should use 1.25" on the stackpipe? Is this necessary? Right now I have a 75 gallon with one return pump. It has a magnaflow stackpipe going into a 1" bulkhead with 1.25" nylon hose. I can see that the water fills maybe half of the 1.25."

[fishgate]

This is almost exactly what I have. I just did it following most of what durso uses. The only difference was I drilled a hole in the top of the standpipe and inserted a 3/8" JG tube above the water line. There is a sweet spot to running it and that involves dialing back the return flow. I am using an Eheim 1250 (950gph).

http://www.dursostandpipes.com/

[jason77777]

So you use 1" pvc for the drains and 1 1/4" for the standpipe? What is a 3/8" JG?

[fishgate]

Exactly! I modified the top because I have megaflows that have two exits and I wanted each return to split off into two. The durso design has that cap coming up and that blocks the plumbing for using the other side.

JG = John Guest. It is that hard plastic line like goes in your RO/DI system.