Anyone else encountered this stuff?
Looks like dirt but dissolves like fairy dust when you brush it.
Usually forms in this pool within 3-4 hours after vacuuming to waste.
Water is in balance, no phosphates. Just started happening this year.
This sounds like the residue that is left after using No-phos. Is it milky in color?
DE powder? Broken guts on filter perhaps?
That's of course you have a DE filter.