[spanko]

UvaJed, your rock will seed your sand with nitrifying bacteria, worms, pods and such. If you want to do more you can certainly add a couple of cupfuls of sand from an established tank. Sometimes you can go to your local fish store and ask for some of the stuff from the bottom of their live rock tanks. Go through anything from another tank though a little to see if there are any bad visible critter before putting it in.