Chlorine Dioxide Liquid is a safe & effective method of disinfecting water. They kill bacteria, viruses & cysts in water, including Giardia & Crytosporidium. They have a quick reaction time & leave much less residual taste than ordinary chlorine. Treats up to 60 litres of water. Once water has been purified it should be kept in a sealed container. The container should be either kept in a dark area where no light is allowed. When using any water treatment product, the water should be relatively clear. If there is debris or any items in the water, this will reduce the effectiveness of the active ingredients. Particles should be removed by straining the water through a piece of cotton or similar fine weave fabric.