I agree with Hara. I have a FOWLR so I tend to move mine around, somtimes. I think you should shoot for 1.5-2LBs of rock per gallon. You can mix base with LR to save some cash. If you are going reef, you might have to consider a more permanent aqua-scaping scheeme. Browse some of the pics of tanks. I like to have a cave or two and a nice pile, maybe a nice cliff. It is really how you like it.