My tank is coming up on it's 3rd birthday. I set it up with about an inch. A year latter I adding another inch or two and added a DSB in my refugium that varies from 4 - 6" deep.
I just setup an new 37 and put a good 5 -6 " DSB. All southdown in this one.
When I set up my 300, i am seriously considering having the southdown in the fuge. I am thinking of putting a sandbed in the main display that is more consistant with what I see on the reefs when I go diving. All the reefs I have dove on, have a much grainery sand bed. Lotsa of rubble and shells, and just gererally nothing like the grain sizes that are required for nitrification/denitrification, etc. I think it might look more natural and burrowing fish would not cause a snow storm. That is my one and only complaint with my current DSB's. I got this idea from Fergy. That is the way he did his tank, and he has a 12 DSB in his fuge.
Something to chew on, no?
Louey