bare bottom vs. dsb

Salt or Fresh?  What are you putting in it?  You should always use some kind of substrate.  It's used as a buffer, I am far from an expert but thats what I have learned.  Who knows what it buffers?

This thread almost escaped without my comment.

From the biological ecological system standpoint, the use of a denitrifying sand bed is definitely better. Perhaps contrary to what some may think, disturbing the sand bed is a good thing, in moderation, and in a properly maintained reef, the stuff found in the sand is full of life rather than lifeless.

As far as aesthetic considerations, you know better than anyone what you like the look of.

I believe that when Zoanthids attach to a bare bottom the tank will begin to suffer because of trouble removing detritus. (Fishgirlheather, please won't you come back and let us know how it's doing at one year.)

The bare bottom idea is far from new. It is called the Berlin System and was mostly abandoned in favor of Natural Nitrate Reducing (NNR) sand systems which, when set up and maintained correctly, offer several significant advantages over every other system that has ever been tried.

Now when it comes to a "clean sand bed", in nature they are actually few and far between. But many people want their tank to have the appearance of the white sandy beach we see in vacation pictures, and getaway tourist brochures. Ironically, there are miles and miles of less than pristene substrate that exist for the sole purpose  of providing tourists with that one white sandy beach. (I suppose this is where a large refugium with a DSB could be used to advantage.)