Thank you both very much.
JamesW, are you saying that I should subtract CYA in ppm from TA in ppm and use that number to determine how over carbonated the water is? So a typical example might be a pool with a CYA of 50 and TA at 120 (My pools don't use borates). The Carbonate Alkalinity would be 120-50=70. Then I could take that number to the chart chemgeek provided and see how readily the pool will off-gas CO2. So based on the chart, for the situation I just described, anything with a pH of 7.3 or higher wouldn't increase due to aeration, unless TA was increased first. Does that sound about right?
I'm not sure I understand how cyanurate adds to alkalinity. How is cyanurate different than CYA?
I'm still trying to connect the dots here. Is there a way to predict the potential change in pH when CO2 is lost? In other words if you move up a given column on the table, what happens to the pH?
I feel fairly comfortable with the idea that for a given pH and TA, I can get a sense for how readily the pH will climb. In the red, it would be hard to prevent it from climbing, orange, should climb if aerated, and in green, probably won't climb without some serious effort. I'd still like to get a sense for just how much the pH could potentially climb. So if I'm in the red, and I aerate, the TA will drop (potentially to where the orange and green meet), but where will the pH rise to?