Quote Originally Posted by chem geek
It turns out that this questions come up quite a bit as people think they should run at lower pH to get greater chlorine effectiveness and don't realize that when CYA is present this inhibits their ability to do this (i.e. to lower pH to increase chlorine's effectiveness).
The reason that people think that is that every singple pool publication I've seen fails to consider the effect of CYA on the HOCl / OCl levels in pool water, and pretends that the simple, no-CYA, curves still apply. Of course, they don't.

I've known this for a long time, but until Richard got his calculations to the point where they are today, I had no way to actually quantify the effects.

-- Richard, it would be great if we could come up with a set of graphs, to publish here, alongside of the simple Cl / HOCl / OCl 3-hump graphs that are present in all the pool manuals. A visual representaion of the *real* situation would be a good first step toward combating this almost universal error.

Anyhow, you have my gratitude for all the work you've done. I think it has the potential to help a lot of people. --

Ben