I agree with Tony - With the sump, you want to have the water in there as long as possible for heating, skimming, etc.
I've got about 1.5x turnover if not less - s'all I need the system for it to skim, heat, sterilizer and push through carbon. It's in the bedroom so it's quiet, no problems, makes me a happy camper
Every now and then it sounds like a big monster is sucking dry the bottom of a slurpee container, but that's easily fixable, sometimes - usually without TOO much swearing and adjusting of chaeto :P