Because I like the sand look so much, in my 20g nano I am setting up I am doing a DSB in it, but am willing to replace it when it becomes a problem.

and what would the problem be that you would have to replace the sandbed over?

May be gettign dirty really easy or Cynao and he can suck out the cynao and replace the sand for the tank....

I agree, bare bed just seems so sterile.. so LFS like.

But Greg we have one up on LFS were better then they are.. I love my Bare bottom tank lots of flow for the crap to stay lifted for the overflows to pick up..

:D I guess that is true! If I was doing a tank that was SPS dominated I might consider it.. but I would miss the sand though

The sand bed can become a "problem" in that detrius can build up in/on it, and make it more difficult to control nitrates, algae growth, etc. In my 180 display tank this is not a problem because I have lots and lots of sandsifters and really high flow, so all my detrius that settles gets kicked back up into the water column, then into my filter floss in my sump then out of my tank. In my nano this might be more difficult because it wont be enough sand to keep a dragon goby or some other sand sifters healthy, but maybe there are some smaller gobies that can do the job for me, then I wont have to replace the sandbed, if I keep my flow high and use mechanical filtration.

I think it depends on what kind of animals you want to keep. I went barebottom because I wanted to keep sps and I think it is easier to keep the water cleaner with a BB setup. Still, I use a Fuge with a deep sand bed and grow Macro Algea