Disinfection with chlorine (inorganic). Fast-dissolving inorganic chlorine granules with about 70% active chlorine.
Shock chlorinating the pool water is important, this to saturate the pool water with chlorine at start-up and to really break down minerals, bacteria, algae and other inorganic and organic dirt in your pool water. The bathing water feels good to get a shock chlorine treatment at regular intervals during the high season. Feel free to add after days with a lot of swimming and warm weather to compensate for the increased chlorine consumption.