Not sure if this helps, my 55gaklin tank with an eshopps over flow rated at 600 gph, I had an ehiem rated for 562 full open, now I have a jebeo dc6000 on the third setting putting out more and also running a gfo/carbon reactor , as far as flow threw the sump, it out what u want threw it, might want slower flow so that skimmer or refuge will pick up more, I always adjust mine for noise even if it's slower, flow in the tank is the crucial one not the sump, don't worry about all that times crap!!!
