I have a few questions about using sand instead of gravel. A local pet store recently moved to a new location and had a sale on their used tanks, so I picked up a 15 gallon for 10 bucks, which I didn't think was a bad deal. They also had a 20 long for 20 dollars and a 45 gallon for thirty, but I'm running out of room in my apartment, soooo...Anyway, they didn't have any sand at the store I was at, I guess because they don't have much of a saltwater selection. I did see some "edible reptile sand" but didn't figure that would be a very good choice. So anyway, I went to Lowes and ended up getting a 50 pound bag of Quikcrete Playground Sand. I liked the look of the "All Purpose" sand better, but it had some warning on the back about the dust potentially causing cancer, so I didn't really want to have that in my fish tank. Anyway, since the sand I bought doesn't say what kind of rock or whatever it's made from, I was was wondering if anybody had ever used this before? If so, did it change your water chemistry at all or anything like that? Thanks.