Should I reduce my drains?

SallyWho · Jun 22, 2018

I have an 1800gph Modular Marine overflow, and a Jebao DCT8000 return pump for a 120g tank. I know the overflow is a bit overkill for the tank size, but I wanted the extra room in the exterior box to work in- I've heard the exterior boxes are narrow enough to make it hard to plumb the bean animal system. The overflox box has three 1.5" drains. I do plan on putting a gate valve on the primary siphon, but is a 1.5" drain a bit big for my purposes? I plan on doing 1" returns, so should I just leave the drains at 1.5", or reduce down to 1.25" or 1"? I think I read somewhere that your drains should always be a bit larger than your returns. What are your thoughts, plumbing experts? Thanks!

hijinks7 · Jun 22, 2018

No 1.5 with a gate valve is fine. I run 1.5 drains on my 120g with two return pumps going back with 3/4in returns. Works just fine. The key is the gate valve so you can tune the flow and it'll still create a siphon.

Randy Holmes-Farley · Jun 22, 2018

Size aside, I'd always try to have an extra drain or two that are only used in emergency (e.g., a plug in the normal drain(s)). In my 120, the overflows each had two drains, and one in each was a long PVC tube open at the top just above the overflow water line but below the tank lip.

SallyWho · Jun 22, 2018

hijinks7 said:
No 1.5 with a gate valve is fine. I run 1.5 drains on my 120g with two return pumps going back with 3/4in returns. Works just fine. The key is the gate valve so you can tune the flow and it'll still create a siphon.

Thanks! Think I should go with a 3/4" return instead of a 1"? I was going to do a 1" return mainly because I already had a drill bit that size, but if a 3/4" return works better in terms of flow, I'll get another drill bit.

Randy Holmes-Farley said:
Size aside, I'd always try to have an extra drain or two that are only used in emergency (e.g., a plug in the normal drain(s)). In my 120, the overflows each had two drains, and one in each was a long PVC tube open at the top just above the overflow water line but below the tank lip.

Yup! In my overflow box, I'm going to run a primary siphon, a secondary siphon, and an emergency drain. If I can tune it in right, should be silent and safe (hopefully)!