I want to switch my 20g long to the black sand too for the puffers i'm going to get, becuase I think that It'll look awesome. The colors of the dp's and the shrimp will look awesome contrasted from the sand. I heard that it really shouldn't get sucked up by the vacuum either, is that right? The onlt problem for me is taking out the old stuff I have in it now with the water still in it.