I may have gotten a junky brand of sand, but some of mine ended up floating at the top of the tank, clogging up the filter. The "How To" Clean sand video I watched said to gently mix the sand up so all the particles in it would come to the service, but when I did that, it just caused a whirlpool of sand grains all over the top of the tank that did not settle. Then when I tried to take it out of the tank, it got stuck in the corners of the tank, and it was just a mess. I cursed up a storm that night. Lol, but I have low patience, so maybe that's why?