I just measured my fill water, straight from the tap and after sitting for 24 hours. I know that straight from the tap will have a lower pH than later after the dissolved CO2 is released as the water goes from water main pressures to atmospheric pressure.
pH 7.9 from tap
pH 8.4 maybe after 24 hours, hard to be sure color was above my testing kit max at 8.2, guessing at 8.4
I notice that when I put these values into the Pool Calculator, using pH of 8.4, that the CSI = 0 exactly.
Is this some sort of universal truth or just a coincidence? At rest, water will balance out the pH to make CSI= 0 at a given TA and CH? Just wondering..... and wondering what that says for chemistry post resurfacing the pool.
Chemistry is not my long suit and so while I think about it and try to understand, I need to have simple explanations and pictures to make it make sense to me.