We're having this build-up around the pool edges, and in the landing zone. I've tried to scrub it with a fair amount of pressure and it doesn't come up. There was a fair amount of leaves pooled here for a bit and I'm wondering if it's some kind of residue. But wondering about recommendations on treating it - I suspect the sides I'll use a cleaner and scrub it when I can get back into the pool, but this part won't be as simple.
