Water Purification Tabs Chlorine based Water Purification Tablets. Use either before or after filtering solids out to the water you need to drink. 1 Tablet sterilizes 1 liter of water. In case of Bilharzia use two tablets. Small, effective and at a good price. Store in your International travel bag, Bug out Bag, Vehicle survival kit, IFAK or hiking backpack In stock and available for immediate dispatch.