I've heard of this too, but would be careful.. Regular sand is high silica, and may cause outbreak of diatoms / brown algae. Better of getting some live reef sand or just use standard substrates. In my opinion.
Broomer
Yes there is a play sand you can use. I
have it at my Home Depot. It is called Southdown
Play Sand. It is actually oolithic sand from the
Caribbean...sterilized and all. It is in clear
plastic bags with orange and blue lettering
on it.
It cost me 3.74 per bag 50# bags, so needing
500# saved me a chunk of cash.
Bruce