I have been using zeosand for about 4 years. This year I am getting green sediment on the floor of the pool. Initially thought it was pollen, then dirt, then zeosand from the filter but it was too small to be zeosand. It will vacuum up but it returns the next day. Vac to waste does the same thing. Reading these posts it seems that it must be zeosand broken down into dust??? I just put in some floc to see if I can get it to coagulate and vac it up. Has anyone ever had this problem after a few years of perfect performance of the zeo? What kind of maintenance is required of zeosand? I see some stuff in the pool stores for zeosand cleaning/regeneration, but never used any. Any info would be appreciated.