Originally Posted by sarahspins
Petco's "sand" is really fine gravel (and a manmade material), it's NOT actually sand. It will float on surface tension and no amount of "soaking" it stops that behavior. Real sand sinks. Caribsea sands (Tahitian Moon, Moonlight, Torpedo Beach, etc) are all fine. The Tahitian Moon (black sand) is actually a coal slag product like Black Diamond is... so if you want that and want a lot of it, there's no reason to pay extra on the Caribsea. The Moonlight sand is very very fine.
I'd second the suggestion for PFS or Black Diamond (I've used both), but with the Black Diamond, get the finer 30/60 grit not the 20/40 if you go that route and have a choice (some stores only carry one or the other, so if you get what you can get that's okay, the 30/60 is just finer and looks a bit nicer). Pool filter sand is 100% silica sand and does not contain limestone or any of the other junk often found in "play" sand. You can get the PFS at Home Depot or Lowe's, or any specialy pool store. Leslie's store brand sand is sometimes more "white" than tan, so if you want a really white sand for cheap you might check that out.
Just wanted to add, that you can for sure get the black diamond sand at TSC, and I'm almost postive you can get pool filter there too, but it might be play sand. (this is IF you have a Tractor supply in your area)