It recently came to my attention that Sodium hypochlorite is possibly the best option for point of use water purification.
Sodium hypochlorite is sold commercially as “ Dakin’s Solution “ or “ Eusol “.
Simple recipe, and the components last MUCH longer and are multi use compared to pool shock. Smaller storage footprint. Can be used for dental endodontic cleansing.
http://www.virginia.edu/uvaprint/HSC/pdf/09024.pdf
Directions on use for cisterns:
http://www.eastfremantle.wa.gov.au/uploaded/pdf/rain.pdf
General info:
http://en.wikipedia.org/wiki/Sodium_hypochlorite
I read to NOT use sodium based for drinking. it said calcium only for drinking. need to research futher.i