1. S

    Spotted dark-green algae

    Woke up to clean water with many spots on dark green algae. Spot of algae gets removed with a brush and the spot keeps floating in the water (does not dissolve). Total chlorine reads zero, free chlorine was also near zero. I started SLAM, but I'm curious about this type of algae. Usually in the...
  2. J

    What is this spot?

    I have a brown spot on pool sidewall that isn't going away. I have ph at 7.2, chlorine at 30 ppm 6 bags of shock, and cya is 50 ppm. Brushing 3 times a day, however spot grows yellow shell after 24 hours. I attach a picture of after I brush, and 24 hours of growth.
  3. tmisleh

    A little help Diagnosing some spots

    We finished our owner/builder pool up about 6 months ago and I thought all was well. I downloaded Pool Math, set up my subscription, and started logging my tests. The water has stayed crystal clear since day one, and for the most part, I've been diligent on the maintenance and chemical...