I agree with broomer. I like the under tank fuge/sumps, they give you more water volume as well as more room for equipment in the sump and more filtration in a fuge. As far as the HOB's, I think they are a good idea, however there isn't much room for anything on the back of the tank after it is added, and there's not much room in the fuge for macros. The good part about a HOB would be the pod culturing capabilities without the DIY projects.