Pool water chemistry school doesn't mean that they know all there is to know nor that everything they know is accurate. Even the NSPF CPO course has some errors and a lot of omissions. I write about this in the following post:

http://www.troublefreepool.com/certi...ht-t18432.html

I am also going through the IPSSA Basic and Intermediate Training Water Chemistry manuals and they have similar errors and omissions.

The biggest problem is a complete lack of understanding of the chlorine / CYA relationship which is a primary principle of BBB that keeps all our pools algae-free at low cost.