Please help... 13,000 gallon inground pool. Have ozonator and use Trichlor tabs. My CYA level was 175 and drained 75% of my pool water on March 21. Retested my CYA after refilling and it was 20ppm. Chlorinator set on 2, and can't get FC level over .5ppm. Have been using liquid bleach to support the chlorine level..Water is crystal clear and no signs of algae.
Thank you for your help.