I use play sand in one of my tanks, it's great. Pool filter sand has a larger grain and many people prefer it (my HD was out so I got play sand instead), but play sand works as well. As said, it's really easy to clean since debris collects on top. Some people have had problems with sand getting into their filters and recommend a sponge over the filter intake. I think it's a good idea and I use a sponge both to protect the impeller and my shrimp/snails.