I would love to know the difference between total alkalinity and high pH. I have a very basic (sorry about the pun!) knowledge of chemistry, but I always thought that adding baking soda to water would make it more basic and raise its pH. Does it have the same effect on the pH of the water as borax or soda ash, or is there a different process at work?
Also, what am I really controlling by keeping the TA in my pool between 70 and 90 (is that ppm?)? What are the consequences if it's too low or too high? Since PoolMath has "90+" for the upper range, does that mean there's no upper limit, and is more always better?