I have been adding 3-4 ounces of poly 60 every Sunday for the last 2 years. Pool has been perfect Can't thank the folks on this forum enough for getting me there. Ran my cl levels around 5-7 last yr b/c cya was high. Run cl this yr b/t 3-5. As chem geek mentioned an accidental drop has not caused a problem. I am probably over cautious b/c after dealing with Mustard Algae in the past I am paranoid