Ive recently switched my fry tank from grav to sand(prepping for shell dwellers) and have found it to be great...the fry wont burrow, the deritus sits on top, and with careful vacuuming it works a treat.
I was considering sand, but don't know much and have heard "it looks better than gravel, but isn't all that great". And i've also heard it can clog filters and you have to rinse it quite a bit before it goes in the tank, and that isn't all that easy. BUt, I'm definatley open to it if someone can give me a bit of info on it
the only problem with sand is that the water doesnt flow through the sand too well and this can cause aneorobic(sp?) bacteria to grow inside the sand. it's probly fine though if you dont have it too deep or if you stir it up every now and then (or have fish that burrow, cuz they'll stir it up for you.