Having read about this "True Total Alkalinity Reading" value and it's formula -> TA - (CYA/3), should I consider it with my water tests?
In the Pool School Recommended levels for Plaster (with Bleach), TA should be 70-90+ ppm. But if I pay attention to this "True Total Alkalinity" formula, and if my CYA is about 30 ppm I end with some value that is almost always less from just reading the TA results from the TF-100 test kit.
From TF-100 test kit reading: TA = 100 ppm
From "True Total Alkalinity" formula -> TA - (CYA/3):
> = 100 - (30/3)
> = 90 ppm
So, is my TF-100 test kit's TA reading of 100 ppm good enough because if plug it into "True Total Alkalinity" formula it equals to 90 ppm? Or should I discard this "True Total Alkalinity" formula and only pay attention to my TF-100 test kits, TA reading alone thus my TA still needs to be dropped by 10 ppm?