This is my first year with a pool, which came with the house. The pool is about 12000 gal, in-ground, vinyl, with a 3/4 hp pump and DE filter. Figuring that DE came from the gound, I've been allowing the backwash water to flow onto the lawn. This leaves some DE on the surface, but it seems to be washed in after even a modest rain.
Now I read that DE contains crystalline silica which is a carcinogen when inhaled. The sources state that used DE should be considered hazardous waste and disposed of accordingly. (See this MSDS, for example.) What do people do the backwash water from DE filters? If you do collect the used DE from the backwash water, how do you do this? What do you do with the DE after it's collected?