Quote Originally Posted by JimK View Post
Is there a particular reason this higher level is required?
Yes, it has to do with the chemistry at the electrodes, as well as the issue BigDave mentioned. I think it's been covered in the China Shop by Chem_Geek, but I don't have time to go poking around for it right now.

But, your cells will last longer that the higher level, since cell life is proportional to ON-time, and they'll be on less at the higher CYA, even with the higher required chlorine levels. Read through the Best Guess page, linked in my sig, for more info.