. I think the 9.5 would be way too powerful for a fuge. I'd go with your Mag 7, or perhaps even a Mag 5. You don't want it to go through too fast, as it'll disturb the plants. As far as the overflow box, the thinner and longer the actual overflow portion is, the more surface water it skims, and the more DOCs it catches. As for the side outside the tank, whatever size can accomodate your PVC
pipes. So if you're going with 1" pipe, make enough room for those, and I'd recommend a little more room around the bulkhead for cleaning/comfort. It really is up to you as far as the area exposed to the water...but (looking at the tank from the front) the greater size the overflow is from left to right, the better than it would be a square, and better than it would be front to back. HTH
, if you need, ask more questions...I'm moving my little African Cichlids upstairs, and they're lookin' at me like I'm insane. Who's to argue with 'em!
125 gallon saltwater: 55gal sump, 4 Blue-Green Chromis, Purple Tang, True Perc, Firefish, Royal Gramma, 5 Ricordea, Bubble Coral, 15 Pulsing Xenia, Green Star Polyps, Deresa clam, Green-Tip Torch Coral (about 11 "heads"!), Orange Montipora Cap, Purple M. Digitata, Green Slimer Acro. Yongei, 3 Orange M. Digitata, Pink&Green Acro. Millepora