In a separate post, I was told to SLAM my pool. I have been reading every article I can find but I'm a little unclear on how to lower the PH first. The POOLMATH tells me how much muriatic acid to use, but where do I buy that? Are there different strengths? Can someone link me the info on how to lower the pH (where to pour the acid, how long it takes before I start to SLAM, etc.) Also, how do you know when you are done SLAMing? And before it is safe to swim in again? Also, my CYA (Intex swg) is reading at 85, is that too high?