If you're not purposely trying to keep them super shallow you can also just build them a little higher for more water volume. I grow all my zoas out in deep blue 60s.. 48x24x12.. The 12" lets me line the entire outside of the frag tank with magnetic frag racks.. I can also eggcrate the entire bottom and then build platforms for higher light palys and zoas. Works well for me. For selling them a shallower one is good for photography and for people to look at them close up...