Calculate sump return

[clarityreef]

Hi guys,
I have a 26gal cube tank with an eshopps overflow pf300 and a 12 gal sump. what rating should i have the return pump? recommendations?
I have a spare eheim 600, would that be enough?

 

[Mrramsey]

I would think 125 to 150 GPH after headloss. The eheim 600 is 160 @ 0' of head so I'd say it is too small. The Eheim 1000 would probably be a much better fit.

 

[stancfii]

With that size tank and sump, you really don't need more than 50-75gph on the return. All you can do is try it out, it certainly wont hurt anything. If you decide it needs more flow, then upgrade.