The shock chlorine removes chloramines (spent chlorine) and other contaminants. Very good to occasionally drain some water and refill with new "spa water". Shock chlorine is the same preparation as day chlorine but in granulated form. A rapid dissolution of the granules gives a rapid and powerful increase in chlorine in the water. Both day chlorine and shock chlorine raise the pH of the water. Thus, the pH should be balanced with pH-lowering agents after each shock chlorination.
Shock chlorinating the pool water is important 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. Bathing water benefits from a shock chlorine treatment at regular intervals during the high season. Feel free to add after days of heavy swimming and hot weather to compensate for the increased chlorine consumption.
Dosage: At the start of the season, calcium chlorine/shock chlorine granules are added. During the season with high bathing load and/or high temperature, the dosage should be increased. See instructions on the packaging for dosage. For shock treatment use 60-80g/10,000 litres of water (100g1dl). Repeat a shock treatment every 5 weeks throughout the season, and as needed.
Handling: Dissolve the right amount of granules in a bucket of hot water. Always add the water first and then the chemicals. Then gently add the solution to the pool drain or along the edge of the pool. Always read the label and product information on the package.