This may be a stupid question. Is the CYA in pool water not part of TDS (because it is an acid and not a salt) or is it part of TDS? I realize that the magnitude of the ppm is very small compared to the ppm of TDS. I'm thinking about the effects on TDS of spa BCDMH vs Dichlor, and my assumption is that the DMH is part of TDS but the CYA is maybe not.
