Hi, Ted/John

We're sort of hijacking this thread but, yeah, I'm in the dark as to the wide variance as well. My last CYA addition of 11 lbs (35ppm) tested complete after 48 hours.......possibly sooner. I wonder if the age of the product has any effect.

Ted, what are you doing putting that stuff in the pool where the customers can see it? HIDE it in the filter!!! If they backwash, you get to sell them more!!