Steve, you might want to consider talking to Dan about building you a fuge. I think you may have some problems getting a 20 gal. drilled. Dan could probably build you a fuge for not much more than what its going to cost you to retrofit the 20 gal. All you would need to do is hook it up and go. I'm not really sure how you are going to use an eclipse top (other than the lights) as part of a fuge. You don't need the pump, filter, or biowheel.