The US Department of Health recommends using 1 Teaspoon (.17 Fl oz) of unscented 5-6% household bleach per 10 gallons of water for purification of stored water. In our case, we use (have been using for 37+ years) 1/2 ounce per 50 gallons (2 each 50 gallon tanks), a concentration of .005% sodium hypochlorite, without evident difficulty to health or equipment.
Sorry but I filter the water going in the tank... coming out of the tank and use carbon/filter media for using the water for general use... there is NO chlorine for me to ingest period... to each his own... but I'm not going by the 'US Dept. of Health' to recommend how much chlorine, iodines, perchlorates, dioxin, phenols, pyrethrins, or any other petroleum distillates I should be injesting... YES the US Dept. of Health determines how much is tolerable in your water or foods... do you trust them? I don't so that is why I try to avoid any chlorine or other chemicals in my drinking or cooking supply...