I have a tank that I'm in love with, but it's drilled with an already-installed overflow though no plumbing currently. Can this be used with a freshwater setup? I didn't think it was possible but I keep thinking about it because I want it to work! Could I plumb it for use with a canister filter instead of a sump? Or would I need to just have the holes plugged? Another thought I had was converting the overflow to an actual filter; plug the holes at the bottom, fill it with media and somehow install a pump in the bottom to force the water to flow through it.