I keep reading about people that dont want deep sand beds, or even have bare bottomed tanks- why? It seems to me that the deeper the sand bed, the more likely a host of beneficial organisms will develop there, and you can have sand sifting creatures to clean it. Am I wrong? Who here runs a deep sand bed? I have also heard about rocks topling from creatures burrowing in it- wouldn't you just set the rocks on the bottom, then add the sand around it?