I recently set up(6 months ago) a 55 gal tank with about 60lbs of live rock and a plenum in it. The rock is about 70% covered with coraline. My problem is that I have a constant snow storm of fine particulate matter that circulated in the upper one third o fhte water column. I thought it would go away once the sand devloped a biofilm on it but it has not. The particulate matter appears to be created by the hermits in the tank picking at the live rock. Any suggestions on how to rid my tank of this problem?