I can’t really see what it is in the picture, but I used to get tiny, almost invisible particles of something floating all over the surface of the pool every morning. I changed to filtering 24/7 and whatever it is now collects in the skimmers, floating on the surface inside the skimmer housing. Whatever it is won’t wet and on days it’s enough of whatever it is to form a layer in there, I can scoop it out of the skimmer housing with a plastic cup, and it’s dry like ashes. I assume it’s insect or plant sourced — maybe spores of some kind — seems to come and go. Anyway, do you skim with your filter 24/7? May be worth a try to see if that helps.