Good old bleach is great, but treatment tabs have advantages.
In the first part of our three-part series covering onboard water quality, we discussed protecting the tank with basic filtration and securing the tank vent. Further action is required, however, as the tank and its contents will always be far from sterile. Municipal water is filtered to remove turbidity, disinfected (typically with chlorine, ozone, or ultraviolet light), filtered once more (often very fine filtration to remove cryptosporidium cysts, which resist disinfection), and disinfected once more (with chlorine or chloramine) to protect the water while its in the distribution system. However, since we are storing the water on our boats, this process of secondary disinfection becomes our responsibility. So what are the options for treating water that is already in an onboard tank?