The overflow and the return pump is that what dictates the gallon's per hour. DO the baffle's slow it down or any thing. THe reason I ask is im planning a fuge and would like to keep the overflow and pum i am currently using.
if you were to have very very tiny gaps between the bottom of the sump and the baffles, then maybe you'd have flow issues, but the gaps for baffles allow more water through than the u-tubes.