My local Home Depot used to have southdown playsand, i actually have a bag from when my parents redid their pool. I just got back and now they have tropical play sand, silica free, sterilized, made by oldcastle stone company of somewhere in PA. I bought 100lbs, $6 for 50 lbs. It says on the bag that it isn't recommended for aquarium use, but this stuff is what I need for my dsb right?