I noticed some black spots around the tile grout in my pool and was wondering if it’s black algae or not. Tried scraping with a toothpick and not really slimey. Just breaks off like I’m chipping away grout. Won’t come off with chlorine tab or extensive brushing. Just when I scrape with a toothpick. Let me know what you all think…
Fc=3
TC=3
Ph=7.7
Alk=120
CH=360
CYA=40
Fc=3
TC=3
Ph=7.7
Alk=120
CH=360
CYA=40