Is TA 140 too high?

[CarlD]

Carl - you may have missed it. In his signature line, he says he has gunite.

Yeah, I did miss it--I was writing in the midst of 3 insane days at work.

For a gunite pool, the T/A should be in the 80-120 ppm range (sometimes the top is 125-statistically insignificant).

[waterbear]

For a gunite pool, the T/A should be in the 80-120 ppm range (sometimes the top is 125-statistically insignificant).

Actually, the NSPI (now APSP) standard recommends 80-100 ppm TA for liquid chlorine, cal hypo, and lithium hypo and 100-120 ppm TA for chlorine gas. trichlor, dichlor, and bromine. The pool surface is immaterial. This is actually sound and based on the chemistry involved. Chlorine gas, trichlor, dichlor, and bromine are all acidic and become even more acidic when they sanitize. A higher TA with it's tendency to create a pH rise helps offset this.
The unstabilized chlorines are all alkaline and have an acidic effect when they santize and are converted to chloride ions so their net effect on pH is neutral to slighly alkaline. Therefore they benefit from a much lower TA so there is less outgassing of carbon dioxide (since the water is not 'carbonated' as highly) and therefore a more stable pH.