Thanks marc for so much info on sumps, as I am deciding right now if I should use a sump when I start my 75 gallon (reef) up, I have a good idea on the other componets (lights, skimmer, ect.) but I had no idea on sumps. I have ! 1/2 years experence on a 5 gal nano so I am a little overwhelmed by sumps. YOUR articale did make me think that I might be able to put a sump in to start this tank. I am weighing my decsion carefully, thanks for giving me so much needed info.