[Newt]

I've seen it at Petco but not all the varieties. No, I do not buy fish there. My son likes to go and look at the birds and other animals.
I'd be careful about the phosphourus claim. I once had a substrate that had phosphate in the rock (didnt kow it when I bought it) and I had all kinds of algae issues until I switched to Flourite.

 

[Newt]

Learn the DANGERS of dihydrogen monoxide, some times referred to as dihydrogen oxide:
http://www.dhmo.org/facts.html