Split drain or split return?

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I'd be looking to keeping the drain as quiet as possible using something like a Herbie (with one drain having full flow and the other drain dry).

Wouldn't get too worried about an exact turn over formula through the sump but often see the gph rating of the skimmer being a minimum but nothing wrong with having the return flow contributing to the overall turn over of the display.

Again my focus would keeping things quiet.