Not sure if this is a problem with the calculator or an odd inflection in the CSI formula or what...
If you punch in certain values (which are close approximations of my pool currently unfortunately: PH = 7.2, TA = 110, CH = 675, CYA = 360, Salt = 0, Borate = 0, Temp = 83), then it shows a CSI value of -0.82...corrosion likely. That doesn't sound good. Well I figured the easiest adjustment is to increase PH since 7.2 is kind of low anyway and surely increasing PH would make corrosion less likely. However, if you keep those numbers but change the PH to 7.4, the CSI actually plummets down to -3.36.
Here's a screenshot of the values using current and goal to see them side by side:
I think the mega extreme CYA level and the very high CH level are just making the calculations wonky...if you increase PH further to 7.5, the CSI just goes NaN. Can anyone explain what's happening?