Different strokes for different folks. In the 93 I have an extremely shallow sand bed and don't vaccume it. I have two rays in the 210 that keep it pretty stirred.
I chose not to vaccume, however I recommend it. Hypocritical, huh?
I don't feed very heavily, and I have a huge pod and worm culture growing down there, and I figured that I might as well leave their little Eco system alone.
For a heavily fed tank, this won't work as well.