Explanation of how the chemistry of chlorination works. Chlorine first must overcome the oxidant demand: metals, then non-living organics and ammonia-based compounds (chloramines). Only after the oxidant demand has been destroyed is the breakpoint reached, and sanitation can begin.
Calcium out of the tap: water chemistry lesson with Harold Evans
All water chemistry starts at the tap. You must test the tap water to know the baseline for water treatment. Test for calcium hardness, pH, alkalinity and temperature. Your plaster surface depends on it. Learn why it’s important to add calcium flake to the water, instead of letting the calcium levels in the pool “drift up.”
Regular backwashing is ineffective if your filter has a channeling problem. Water is avoiding the sand and finding the path of least resistance. In these cases, water was going around the inside of the filter tanks.