I have a 37 gal. tank (30" wide) w/ 40lbs of Live Rock, 4" DSB, an Aqua Clear Filter (w/ Carbon - should I take out the sponge?), a heater and 2 powerheads. The tank looks a little crowded w/ everything in there. Someone suggested a sump. I can only fit a 7 gal. container but I believe it's large enough to house the skimmer and the heater at least. What equipment would I need to purchase to have a sump? I'd appreciate any suggestions.