how many gph for return

[treesprite]

I have an overflow box with 2 1" hoses and need to know the # gph I should have for return, so if anyone would care to make suggestions, it would be appreciated. Thanks.

[Rascal]

For drains, I think I read somewhere 600 gph for a 1 " pipe, but a lot will depend on the amount of head pressure at the intake. A drain at the bottom of the tank will process water at a faster rate than one nearer to the top of your tank.

Your overflow box will have its own rating, independent of the drains, based on the maximum amount of water it can take without allowing the water level in your tank to rise too high. This number will vary depending on the size and construction of the overflow box.

 

IMO you don't want to push the maximums on either of these, though. Better to have some extra overflow and drainage capacity to deal with the inevitable slow downs in flow that will come from algae and/or critters getting caught up in stuff.

 

How much flow are you trying / hoping to get through your return plumbing?

[jamesbuf]

You need to get close to the 600gph per U-Tube because air can pool in the top of the U-tubes if there isn't sufficient flow. If enough air pools in the top, you'll lose suction and the main tank will overflow. So if you use just one U-tube, then try to get between 500-600gph and if you use two U-tubes, then try to get between 1000-1200.

[treesprite]

Its a CPR overflow box - there are no U tubes. Actually I just found something that says 1200gph is the flow rate from the box, so then do I want to match that? Does it matter that the tank is only 45g?

 

The one I have it the last one on this page. I got it used.

http://www.marineandreef.com/shoppro/CPR_overflows.htm

Edited September 5, 2007 by treesprite

[dbartco]

I would not even get close to that. If you can get by with more in tank circulation the better. Mag 9 (or equiv)max IMO, which at 800gph @ 4ft head is fine.

[NRehman]

The overflow does not need to have a high flow. The in-tank/closed loop circulation/pumps should be the one that provide the tank flow.

[Big Country]

You have the same overflow that I am running on my 75. I'm using a mag 9.5 for a return pump and it's doing fine once I adjusted the tubes in the drains to cut down on the flushing noises. Just make sure to use the aqualifter pump to keep the air out of the overflow chamber or it will get a air bubble and break siphon.

[davjbeas]

For a 45 gallon tank I would go with a mag 7 for the sump return.

I am using mag 7 pumps for my 75 gallon reef and 55 gallon FOWLR tank. it is plenty of flow.

 

David

[treesprite]

Thanks guys.

 

I do have an Aqualifter pump to use with this thing.