I have a sand bed that is only about 2" deep and parts of it are constantly stirred up by an active pistol shrimp and a couple of watchman gobies. My question is should I avoid other things that stir up or oxidenate the sand bed like nassarius snails, horseshoe crabs, or sand sifter stars? What are the benefits of having things stirring up and eating critters out of the sand bed verses leaving it alone? Thanks for the input.