be careful with this super fine grain sand as it can easily scratch glass by getting stuck in float algae cleaners. that's not fun. (and being black it blends in easily and is hard to remove). used black sand before and it was OK, it's never as pitch black as you want it though, wasnt as magnificent as i thought it would be. I have barebottom system now but if I go back to sand I'll use the standard white sand.