@MommA2K I use natural, washed, coarse river sand that we buy by the dump truck load from a local quarry. As long as you don’t use play sand (too fine) or construction sand (made from crushed stone and too dusty), you should be fine. I like what we get because there’s a lot of variation in the sizes of the sand grains and pebbles. It’s not too dusty (because it’s washed) and it’s so easy to keep clean! Plus the girls eat it, dust bathe in it, and it doesn’t get too hot or cold.