Hang in here for a second gang. There is somewhat of a line between sand shifting and sand sifting organisms in a tank. The sand sifters are not all that great as they tend to eat the organisms that populate the bed. On the other hand, things like worms, mini-stars, mini-cukes, pods and snails stir the bed but do not eat their roommates. It is the later that you desire to keep a healthy bed. For such fish as gobies, they love to eat pods or worms. When you have these sand dwelling fish a refugium is almost a must.
Sorry about you accident Joe. With diggers it is best to support the rock on eggcrate of pieces of PVC pipe. And
[welcome]