VIAN - Chlorine granules. 1Kg
Free Chlorine should be maintained at 3.0mg/l (ppm).
To raise the free chlorine, add by 1mg/l (ppm), add 2g of Granules per 1000 litres (220galls) of spa water.
Maintain pH between 7.2 and 7.6.
ALWAYS add Chlorine to water and NOT the other way round as this can be very dangerous.