I'm slowly working my way down to a bare bottom from a DSB. Having emptied DSBs twice in my life, I can tell you that after a while they are straight up MUD. I can't say if it is a good thing or a bad thing, but once you see whats at the bottom of the sand bed you might think twice about building one.
I agree with this. After switching tanks or removing the sand bed, the stuff that comes out is horrible. Lol it's some of the worst smelling, gag inducing awfulness I've seen. It's enough to make me want to go barebottom.