I just noticed that so many people use either gravel, sand, or nothing. I'm thinking of using rocks instead, to cover the whole bottom of my tank for a different look. Is there anything sand an gravel gives me that my rocks won't? I think the only problem I'll get is vacuuming inbetween the rocks, so there I'll just use gravel as some filler. What do you think, and what I'm I losing or gaining by using rocks? Because I can't think of much, but a different look, which is nice.