I am having no trouble whatsoever with my bromine/bleach system as taught on this forum. The water is fine. It's the spa cover that is the problem.
Every couple of weeks I notice a patch of slime growing and spreading from a central spot under the spa cover. I just wiped it off the first time. Today, I wiped it off then poured bleach on it.
Any other tips? Anyone seen anything like this? Strangely, though we've had this spa since 1995, this is the first year that this has happened. BTW this is the second cover I have had, this one is about 6 years old.