How much you can pump through your tank is determined by the overflow. Be really careful with lots of pump that can overpower your overflow's rating. My wife fed the fish once and innocently tossed the food container under the stand. It hit the speed adjustment on an Eflux pump and I got the dreaded call while away for work.....
Moral of the story?...protect your knobs...lol
I realize many pumps don't have variable knob that's at risk, but I swear after a power outage some pumps vary the speed they return to.
This deepens my belief in 2 smaller return pumps so that the primary return is smaller and can't swamp the overflow, and the second return pump is dedicated to UV, reactor, whatevs. Having flow while cleaning or messing with one of the returns is really nice as well.