5. pH - The highest that I can measure is 8.0, but the pH is higher than that. How does one accurately measure high pH?
I do similar but slightly different. If reading 8 and I’m not using my pH meter which can measure it directly, then I assume it’s 8, use PoolMath to calculate the addition of acid needed to drop the pH from 8 to my target, and add that. Then I mix, retest, and add more if needed.You don't. Just like CYA, add enough MA to reduce pH .2, pump/circulate 30 minutes, retest. When you get to 7.8, then you can add MA to accurately get to your target.