[reeferjo]

snails Astrae Snail, Nerite Snails
small sea cucumbers, copepods, amphipods, brittle stars, bristle worms etc
here are some good links on sand beds
Deep Sand Beds
How Sandbeds REALLY Work by Ronald L. Shimek, Ph.D. - Reefkeeping.com
The Deep Sand Bed - One Of The Most Effective Filtration Methods. | Aquarists Online | Saltwater Aquarium Resources And Information