First I want to say this site has been a tremendous resource as I am a new pool owner (moved to new house with existing pool) and had to open a pool that had been closed for some time. I now have a crystal clear pool!
However, for a few weeks now what appears to be a super-fine "dust" that settles only on the bottom and angled walls of the pool (not on the vertical walls). Seems to vary from a medium to dark brown. Does not stain, and doesn't seem to appear until the pump is run at which point it settles in streaks, along seams or imperfections in the liner. Pool is absolutely crystal clear with no greenish color, etc. All chemistry is spot on. If it is just very, very lightly disturbed it seems to dissipate/disappear. I vacuum the pool, but in a few hours the material is back. But...if I vacuum the pool and then leave the filter off...no material. I have removed the "finger" grids form the filter, and washed twice now. I have added new DE each time and there is a new gasket on the filter. Very frustrated as I spent so much time getting the pool in swimming condition only to have this very unsightly issue appear. I have searched the web and on this site and it appears some people have had a similar issue. However, I have not seen the issue only appearing when the pump runs. Any thoughts or comments would be great. Thanks!