https://www.amazon.com/Cooling ...

Published by

https://www.amazon.com/Cooling-Water-Treatment-Principles-Practice/dp/0820603708

This book goes into decent detail but is still easy to understand about the chemistries available for cooling water treatment, and namely scale and corrosion inhibition.

From what I understand, Poly-PO4 is more of a cathodic corrosion inhibitor than a scale inhibitor. Organic P such as phosphonates and polyacrylamide and polyacrylates are generally seen as better scale inhibitors.