Also, when I filled my hot tub with the well water, I had a pH of 7.2, and a TA of 400. This didn't add up in my mind, as a high TA should = a high pH. Well, I aerated for 20 minutes and the pH sky rocketed. My Taylor test kit said it was 8.2+. I ended up added about 24 ounces of muriatic acid to bring the pH down to around 7.8. I'm currently sitting at a pH of 7.6, TA of 60, CH of 150. My hot tub is small peanuts compared to the size of your pool. Get your pH down with acid to balance the water. Add acid, aerate, and test again. I also added boric acid to my hot tub, but I'm not sure if it's needed in a salt water pool.