We are closing our pool in a few days with Poly-Quat 60 since the weather has been unseasonably warm this week (low 80s) and the water temperature has risen to 68 degrees. I've read all of the information on here about using Poly-Quat and I'm confused about when to add it and the dosage. The information on Pool School says to add it at half shock level, which is 12 ppm since CYA is 60. A discussion at the top of this page says to add it at normal chlorine level, which would be 7-9 ppm since CYA is 60. I saw another post on here which says to add it at 3-5 ppm, which is a lot less than my normal FC level. Since I'm closing my mesh-covered pool early before the water temperature is below 60 degrees, what is the ideal closing chlorine level to maximize the effectiveness of the Poly-Quat? I understand that it is important not to add it at too high of a chlorine level because the chlorine can oxidize the poly-quat, which can decrease its effectiveness. I also need to know if I need to use the visable algae dose which is 11-17 oz. per 10,000 gallons or the clean pool dose which is 6-11 oz per 10,000 gallons. I don't see any evidence of algae now but a lot of leaves keep blowing into the pool. I'm hoping that the Poly-Quat will help prevent algae until the water turns colder so I want to make sure I add it at the optimal FC level and at the correct dose.