Thanks everybody for your imput! I uploaded some photos of my setup. I don't know how to put them here, but they are in members' galleries.
Not sure I completely understand all the pictures but will try.
Looks like you have an overflow box with three overflows adjustable. Probably to slow down a couple and the third as a safety. For quiet safe operation. I would put an elbow facing down on the third to it sucks water below the water line and less air.
If I understand you sump correctly two of the three overflows empty into a bucket but not the third. The third is also very close to your line to the pump. Therefore bubbles can easily travel from the overflow to the pump input. Put a bucket in there to prevent that.
I must not be seeing correctly as it appears your pump input line goes up and over the sump (HOB), then across to the pump room and down. Not a good idea if that is true. IMHO you need a bulkhead at the bottom of the sump then run directly across to the pump. not up and over.
Finally, in the pump room you could add a pvc bubble trap so that water goes to the pump and not any air.
But then I probably did not "read" the pictures right. Noone says I am any good at setting these things up.
And you sure have a professional looking setup and awesome tank.
bubbles
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water