This is what my LFS uses for their rays. I originally used CaribSea's Aragonite sand and it was the most awful sand I've ever seen. It looked very pretty, but it stuck to my ray's slimecoat 24-7 and also got kicked up into the water easily whenever she moved, thus getting sucked into my filters. I cleaned out my canister filter a week or two ago and found 3 inches of fricken sand in the bottom of it. Yuck. So I did a water change and through a lot of work, took out all that sand and switched to the stuff you're asking about, the Super Naturals in black (the color the store uses). It's kind of like sand, but the particles are less fine and not rounded. They almost look like granules of sugar. They look rough when they're dry and in the bag, but once they're in the water and you touch them, they're actually very very soft and comfortable. Macy seems pretty happy with the change, she still sifts through it looking for food and still can bury herself. I like it so far, it solved a lot of headaches for me. One tip -- rinse it well a couple times before you pour it in, it has a lot of black dust. Also, it doesn't filter through ordinary fishnets when scooping debris out, it will get caught in the net along with the debris because it's not fine enough.
