Chlorine Dioxide tablets are a safe & effective method of disinfecting water. They kill bacteria, viruses & cysts in water, including Giardia & Cryptosporidium. The droplets have a quick reaction time & leave much less residual taste than ordinary chlorine. Each tablet will treat up to one litre of water & once purified the water should be kept in a sealed container in complete darkness or in a container that does not allow light in, e.g. a metal water bottle. If these steps are followed, the water should be safe to drink for 2-3 days. When using any water treatment product, the water should be relatively clear. If there is debris or any particulate matter in the water, this will reduce the effectiveness of the active ingredient. Particles should be removed by straining the water through a piece of cotton or similar fine-weave fabric. Add 1 tablet to every 1 litre of relatively clear water requiring treatment. If the water is very cold or if Giardia or Cryptosporidium is suspected, add 2 tablets per litre of water. Swirl gently & wait for at least 10 minutes before use. Wait for 30 minutes if 2 tablets have been used. The water is now ready for use.