How can I remove the scum line caused by waterproof sunscreen on my concrete pool without taking off the paint

We have a concrete pool that is painted. We have tried Comet, Scum Away, Tile N'All, and several others to no avail. My guards are tired of scrubbing two hours a day:)How can I remove the scum line caused by waterproof sunscreen on my concrete pool without taking off the paint
Goo Gone should work on this mess. I use it for scum even in my bath tub and it just comes right off.How can I remove the scum line caused by waterproof sunscreen on my concrete pool without taking off the paint
Goop works, it is a slimy stuff but it takes out greasy stuff. I use it on my husbands greasy clothes. I would look for anything that works against grease.