intake/return line ?

[sb62nova]

for my first post!
I am starting my first saltwater, fowlr , 135g, cpr overflow,cpr cyclone filter, mag 12 pump. I read the return should be a 1.5". So what size should my line be from my overflow,assuming i run a 1.5" return? Also is it fine to run pvc from the overflow. Thanks in advance. [FONT=Arial, Helvetica, sans-serif][/FONT]

 

[melosu58]

Moved to the General Hardware and equipment discussion forum.

 

[sb62nova]

is this an off the wall question?

 

[CaptainAhab]

In general, your return line should be the same size as the outlet size on the pump. Your looking at it backwards. Your overflow has a flow rating, it's that rating (give or take) that your return pump should match (minus headloss).

So if you have a 1" drain hole (approx 600gph) then your return pump needs to return approx 600 gph to even everything out. Your pump will need to be rated higher than 600 because it will suffer headloss (lose power as it needs to pump the water upward). Each pump has these rating as different heights. You can use a much bigger pump (say a mag12) and put a valve on the return side to dial back the flow or you can put a T with part of the flow going back to the sump to even it out (with a T also to fine tune it).

Solid PVC is fine. The more curves, elbows, couplings, etc will cause more headloss. I prefer flex pipe in and out.. just easier to deal with IMO but to each his/her own

 

[ryshark]

I'd go with a 3/4" return in your situation. There are lots of good options for LocLine etc with 3/4", it is a pretty standard return size. Just make sure your overflow can handle more than your pump can put out and you will be fine. My dual overflows can handle probably 3x what my return pump is putting out, you dont necessarily have to match the two. The more water your return pump puts out, the less time the water will be in the protein skimmer chamber to be cleaned. On my system I have 2x 1.5" overflow drains and 1x 3/4" return with and Eheim 1262 rated at 900gph before head loss. So as you can see my drain handles way more than my pump can put out. Going by ahabs number that 1" drain can handle 600gph, then my overflows/drains can handle 1800gph and my pump is probably putting somewhere around 500gph back into the tank. This works for me and my drains are pretty quiet too.
On a side note, you shouldn't rely on your return pump for flow. Thats what the powerheads are for.