Actually it works rather well. I've used it in several tanks and had no problems I could blame on the sand. I always dump it into a 5 gallon bucket or larger container and stick the water hose in and let it run while I swish the sand around. I do this until the water runs clear other wise you end up with a cloudy tank that is almost impossible to clear. My favorite sand comes from the banks of a clear running creek just south of Crestview, Florida. This has to be sterilized before use but thats's another post.