HTH 25Kg Classic Granular is a non-stabilised chlorine that kills algae and bacteria. It is quick dissolving and fast acting and can also be used as a Shock Treatment. This product treats algae, discoloured water or due to extreme conditions (i.e. extreme weather, high bather load etc.). Use to maintain pH between 7.2 - 7.6 (Marbelite pools) or 7.0 - 7.2 (Fibreglass pools). Dosage: with pump running on filter setting, add 1 cup (250 g) around the sides of the pool in the early evening (based on a 50,000 litre pool). Can be used daily or every second day (maintain 1 - 3 ppm free chlorine).