Shock Treatment is also used to give the spa an extra strong disinfection to rid the spa of algae and other biofilm and to burn off unpleasant chlorine by products (chloramines). There are two common sorts of shock; Oxygen Shock (potassium peroxysulphate) and Chlorine Shock (calcium hypochlorite)
Oxy Shock is the most commonly used and the recommended form of shock treatment for a spa. Oxy Shock is fast dissolving and because it is an oxygen based product it does not give off smelly chlorine compounds. Oxy Shock is the recommended product for spas as it is fast dissolving and dissolves fully.
Shock weekly with 30 grams per 1000 litres of water. Dissolve in a bucket of warm water and then distribute around the spa.
Chlorine Shock (Calcium Hypochlorite)
Although it is not recommended, calcium hypochlorite can be used as a shock treatment on chlorine based spas. The reason why it is not recommended is because it takes longer to dissolve and it produces smelly chlorine compounds. It also takes approximately 8 hours for the chlorine level to return to normal once the spa has been shocked.
Dissolve 15 grams of calcium hypochlorite per cubic metre in a bucket of warm water and distribute around the spa.