I'm going to change my 38 into a 55 soon, and was thinking about using undergavel filtration. Will the two maxijet-600's (160gph each) I have, plus a HOB for a 20G, plus a HOB for a 30G be okay? Planned fish will be either a coal grunter (maybe a couple, we'll see on the $$$) or a cuban cichlid and maybe some small dithers or bottom-dwellers. Thanks! 
