Well...after a near overflow, I think I've gotten my system balanced in its first "dry" run with water going through the overflow to the sump. I have a 75G with a DIY 29G sump that I built. I'm using a QuietFlo 600 overflow, and Eheim 1260 return pump from the sump. The Eheim 1260 is a BEAST! I've got about 4-4.5' of plumbing head and I have had to use my ball valve to reduce flow by about 1/2. By the way, is that OK to back the pump down by that much, or will it hurt the pump? I did a power down and my sump still had about 3" of water space left in the sump...yeah...and the overflow didn't lose its siphon...yeah again. Thanks to Ace and Reefscape for giving me the courage, from a previous post, to just fill it up and flip the switch. I'll be posting a proposed stocking list soon, so thanks for the help in advance. I also need to post some pictures.