I will throw my 2 cents in here. Over the weekend I moved my 30 Gallon with a 2 inch sand bed. I always hated the sand just because I couldn't do anything about the buildup of detritus and I couldn't clean the glass to close to it or I would create a sand storm. So after I had all my fishies and corals into coolers and all the water out for the move, I decided what the hey, out with the sand, in with the BB tank!
Now that I have the tank setup and all the occupants back in, I think the tank has never looked better, and everyone who has come by the house agrees! The corals have better polyp expansion, and I find that my 10K MH light looks bluer without the sand bed. I also find that it puts more emphasis on the corals and the rock as the bottom no longer attracts any attention. I was also able to bump up the water flow to about 30X turn over, and the corals seem to like it.
I couldn't see myself putting a sand bed in a tank again.
