OK so it has been a while since I have posted....everything seems to be going well. One question, my sand is covered in brown stuff, diatoms I guess, and I made a curious discovery today. The sand in one area is white on top, it looks as if a lego man sized grenade went off, there is a hole and the sand is piled around it. All that is in the tank is the 3 damsels, 3 turbo snails, 1 pep Shrimp and the Em. Crab.... What would cause this. It looks ver similar to what happens when you pour water into a new tank, without a plate to re-direct the water and the sand is pushed up and there is a hole, only this hole has sharp edges, as if my crab dug it with a shovel lol....help?