How to determine the correct return pump for a sump refugium?

[Moeshi]

I apologize if this is in the incorrect sub-forum.

I'm installing a remote refugium which will be roughly 5' below the tank surface water.
Since the only purpose of this sump is to cultivate pods, I don't have any flow requirements from my equipment, as there wont be any.

However, I'm uncertain how to determine the correct return pump. The sump is a 40 gallon breeder with baffles installed. The overflow is a custom pvc-fitting I made from leftover plumbing pieces. Although the overflow is capable of handling 500+ gallons per hour, I don't plan on flushing out all my pods with a matching pump at the other end.

Can I install something smaller like a 100 gph pump just to create a soft tickle through the sump?
Asked in another way; will any pump do, as long as it can push the water 5' back to the tank?


Thanks.

[Djturna4thakidz]

Yes, as long as it can overcome 5' head you will be good

[Moeshi]

Alright, thank you!