I have 3, 1 1/2" drain lines, and the 2, 1" return lines, my sump is a 50 gallon aquarium I have it set up as a flow thru sump with the skimmer on one end with the overflow going in the same chamber then I have my bubble traps about an inch and a half apart. The middle will be the fuge then my return. All I have to get now is my return pump. This is my first sump so I'm not really sure how much flow I need, the guy that helped me drill my tank ran pvc from the return holes all around the top of the tank with holes drilled in it, and he said that if I got a pump like the Dart or Snapper it would help out a lot with not needing as many powerheads, but I didn't know they weren't submersible Thanks for all the feedback