Quote Originally Posted by cscannon View Post
What is the relationship between pH and chlorine?
Steve, I don't understand the question. Do you mean if there is a change in chlorine effectiveness with pH? There is, but not as much as those in the industry claim because CYA in the water minimizes this effect so I wouldn't worry much about that.

Do you mean will pH affect the rate of chlorine loss? The answer is yes, to some extent, because higher pH means more of the form of chlorine that breaks down faster in sunlight compared to the form that dominates at lower pH. However, with a lot of CYA in the water, this effect is secondary -- it's mostly seen when there is little CYA in the water such that a combination of no CYA and high pH results in quite rapid loss of chlorine in sunlight.