the filter cannot remove. This combination is also potentially more effective in some cases than even using portable electronic disinfection based on UV treatment. Chlorine dioxide Chlorine dioxide can come from tablets or be created by mixing two chemicals together. It is more effective than iodine or chlorine against giardia, and although it has only low to moderate effectiveness against cryptosporidium, iodine and chlorine are ineffective against this protozoan. The cost of chlorine dioxide treatment is higher than the cost of iodine treatment. Mixed oxidant (MiOx) A simple brine {salt + water} solution in an electrolytic reaction produces a powerful mixed oxidant disinfectant (mostly chlorine in the form of hypochlorous acid (HOCl) and some peroxide, ozone, chlorine dioxide). Chlorine tablets (NaDCC) Sodium dichloroisocyanurate or Troclosene Sodium more commonly shortened as NaDCC, is a form of chlorine used for disinfection. It is used by all major NGO's such as UNICEF to treat water in emergencies, and widely by social marketing organisations for household water treatment where household sources of water may not be safe. NaDCC tablets are available in a range of concentrations to treat differing volumes of water to give the World Health Organization's recommended 5ppm available chlorine. They are effervescent tablets allowing the tablet to dissolve in a matter of minutes. Other chemical disinfection additives Silver ion tablets An alternative to iodine-based preparations in some usage scenarios are silver ion/chlorine dioxide-based tablets or droplets. These solutions may disinfect water more effectively than iodine-based techniques while leaving hardly any noticeable taste in the water in some usage scenarios. Silver ion/chlorine dioxide-based disinfecting agents will kill Cryptosporidium and Giardia, if utilized correctly. The primary disadvantage of silver ion/chlorine dioxide-based techniques is the long purification times (generally 30 minutes to 4 hours, depending on the formulation used). Another concern is the possible deposition and accumulation of silver compounds in various body tissues leading to a rare condition called argyria that results in a permanent, disfiguring, bluish-gray pigmentation of the skin, eyes, and mucous membranes. Hydrogen peroxide One recent study has found that the wild Salmonella which would reproduce quickly during subsequent dark storage of solar-disinfected water could be controlled by the addition of just 10 parts per million of hydrogen peroxide. Ultraviolet purification Ultraviolet (UV) light induces the formation of covalent linkages on DNA and thereby prevents microbes from reproducing. Without reproduction, the microbes become far less dangerous. Germicidal UV-C light in