For the first time ever, my pool has been crystal clear almost from the time I opened it -- and then a water test said my phosphates were over 1000 ppb. NO visible algae. I was advised to use Phos-Free, and did so - following instructions on the bottle & on their website to the letter. After 5 days, pool still crystal clear, I cleaned my cartridge filter. Chlorine was very low and I added what I would usually add every week. Instantly the water turned milky blue, and has stayed that way for more than 24 hours.

What happened? Pool store says this is probably dead algae and if it doesn't clear, they advise using clarifiers. I feel like I was advised to fix something that wasn't broken.

Before doing anything else, I'd appreciate any some advice. thanks.