My technical boiler books all use the “lessons learned” theme, and the following are the lessons I have learned about boiler water treatment.
A medical facility had a major renovation of one of their wings. The renovation included new pipes installed for the heating, cooling and plumbing systems. A few years after the construction, the maintenance department switched water treatment chemicals to one with a pink dye. The dye is used in water treatment to show if a pipe is leaking. If you see pink stains on the ceiling tile, you know it is the heating or cooling water leaking and not potable water.