I put in new sand about fice hours ago, and it's still blowing around like mad. I can't see anything in the tank. The funny thing is, none of the sand on the bottom is being displaced, meaning the sand in the water is more like dust than like sand. By the way, the 295 gph pump in my tank is way too much. When I first turned it on, it blew water over the front of the glass, So I had to baffle it so it wasn't hitting the glass directly. Overall, though, the shizzle is izzle.