I have tried almost everything to fight the microbubbles. I originally had a 30gal sump, in order to stop the microbubbles I had to use a single Mag9.5 cut down to about 70%. I used baffles but the flow was just to high. So I moved the sump into the basement. Its a 100Gal stock tub, filled to about 75Gal. I wanted to use a pair of Mag18s for the returns. They worked but there were still some microbubbles. I tried baffles and eleaborate PVC
tricks but the smallest of the buuble would remain.
I realized yesterday I was fighting the wrong battle. I didn't need to have 1/2 my flow move through my sump. I figure by cutting the flow through the sump in half the bubbles would have twice the time to settle out. Plus I can probobly get more flow through a closed loop than by using the same bulkheads for the sump drain/return.
Good idea about the up and over trick. My question is if I do that how do I insure the water in that overflow doesn't stagnate? A few small holes in the return pipe near the bottom? I'm still a newbie and learning as I go along.