BigDave: No water change, but yes... I stopped adding granular dichlor since I super-chlorinated with liquid chlorine in late July. A mod here recommended I stop adding sanitizer until my FC was at or below 5ppm. I actually added my floater back to the pool in mid August because I was worried about not having any sanitizer whatsoever. The floater holds about 1-lb of 1" trichlor tabs that typically dissolve in about 1 week. But that's the only sanitizer I have added since late July until about 2 weeks ago. I test my water every Saturday, and my FC was still at 7ppm the week prior to this last, minor outbreak.

I buy online from InTheSwim. I've never spoken to anyone there. The information about phosphate testing is right in the Taylor booklet. I can't be the first person to ever decide that testing for phosphate might be a good idea (?)

Anyway, the pool is ready to be closed. I didn't realize phosphate testing was the Loch Ness Monster of pool maintenance. Nothing ventured, nothing gained.