Changing from suction to return

[PoolGate]

Imagine you have a hose with no nozzle. Then place your thumb over the end of the hose to make a stream. The flow is reduced but the pressure is increased. Pool pumps are high volume, low pressure, so you want the pressure in the returns to be sufficient to create flow to the skimmer. Larger return openings would allow higher volume, but less velocity so that the surface flow towards the skimmer would be less.

I actually spoke with someone that is familiar with fluid dynamics and he doesn't believe this is the case. He is saying all things being equal, meaning the pump volume doesn't change, more outlets with lower pressure would have the same net result on water circulation as less outlets of a higher pressure. He isn't 100% certain but said he might model this for fun and if he does I'll share the results.