Almost inevitably, expeditions and explorers will be drawn to areas where levels of technology and hygiene are not the same as they are used to at home. Water supplies may contain bacteria, parasitic cysts (like Giardia) and viruses. This can lead to serious stomach upsets, dehydration and other illness. The most basic form of purification is to use either Iodine or Chlorine and these are key items in Lifesystems widely used water purification range Water Purification Sort By: Default Title - A to Z Title - Z to A Price - lowest first Price - highest first Time Added - latest first Popularity - most popular first Sales - best selling first Chlorine Tablets (Pocket Pack) £3.99 £3.49 Chlorine Tablets 72 tablets pack £5.99 £4.99 Lifesystems Chlorine & Neutralising Tablet Twin-Pack £13.00 £9.99 Lifesystems Chlorine Dioxide Drops £7.99 £6.99 Lifesystems Chlorine Dioxide Tablets £10.99 £9.99 Neutralising Tablets (Pocket Pack) £3.99 £3.50 Neutralising Tablets 72 Tablet Pack £6.00 £4.99     Ok