Dump Return Flow Rate. 75g w/ 30g breeder

[AmatuerAuer]

I am in the process of laying out a 75g Reef tank with a 30g breeder sump. I am new to the 'reef ready' predrilled tank/sump world.

What size return pump should I go with? I understand that my sump will need to house enough water to hold any backwash in the event of a power failure. Still haven't mastered the math yet.

Return pump should be equal to/greater than the rate of overflow into the sump while not being so strong it stops the sump from holding a reasonable amount of water (ie. Enough for the skimme, fuge etc to have an effect)

Ideas? Rule of thumb? Product recommendations - with explanation please?

Thank you!
-AA

 

[zesty]

The rule of thumb in the reef world is 10x water turnover.

So, with the ROT, go for a return pump that can give you 800 gph (or more) at your head height. When I was setting up my tank, I choose a size bigger return pump, so I could throttle it back to match the drain. Otherwise, if your return pump can't keep up with your drain, your sump will get a bit too full.

Does that make sense?

 

[AmatuerAuer]

Excellent. Well said. I would assume you have an adjustable return pump? Throttling back by way of a valve could damage the pump no?

 

[zesty]

Excellent. Well said. I would assume you have an adjustable return pump? Throttling back by way of a valve could damage the pump no?

No is correct. I have a ball valve about a foot uphill of my return pump (Mag9.5) and it's been returning throttled back water for about 2 years now. You should not damage a pump by throttling it back.

This is my return valve, my return pump is running submersed.