Thats probably aragonite, which works well to buffer the water and looks better than play or pool filter sand IMO...but is stupid expensive at most of the retail stores. If you are only buying 20 lbs or so its not bad but you'd spend almost a hundred bucks on substrate for anything bigger than a 90 gal...not cost effective IMO.
ya. i'm going to get pool filter sand this weekend. also i'm getting a rena xp3, slate/lava (still not sure which) etc. i'll start a progression thread asap, so stay posted!
Oh and just so you know I went to home depot today for pool filter sand. It was ~5.30 for a 50 lb bag. You would need at most two... I think that price should make you happy. Anyways it actually is stored in the garden section. (Outside) talk to the pool people if you can't find it. Mine was stuck between a pile of salt and firewood...
Yah I was pleased it was like 1.50 more than play sand. Though you still have to wash it fairly well. (IT is easier to wash and the sand is definitely the right size ie wont be going into the filters easily.)