It's been a good year so far for our pool keeping the water crystal clear has been easy thanks to all the help from folks on this site. A few days ago we were visited from an old nemesis a slight amount of a scum on the surface of the pool. We had this last year and never got rid of it until this spring after we reopened our pool. It very hard to get a picture of but it looks like it could be a build up of sunscreen. It won't suck into the filter because it just floats on the surface after 2 min of swimming our turning our fountain on it's gone never to appear until the next morning when we retract our cover and there it is again. Not sure what to do we bought some scum balls and it sucks some up but not all. The water is crystal clear other then the light scum ,it also only covers about a 1/3 of the pool kind of like a small oil slick . Any thoughts our help ?
As an after thought we have scrubbed our cover with water and a small amount of bleach but this didn't work.
Salt 3100 ppm