Thanks alot Ram, that helps alot.!! Well, my 90 has a 20 gal. long as a sump. I was wondering maybe i could have either the eclipse 3 or 6 drilled or something..and somehow set it on top of my sump, already measured, there is room..is it a bad idea to let gravity do its thing on the sump?..or should it drain into the display tank?..also, what kind of light should i use for it..Thanks alot for taking the time to answer, i apreciate it.