Gary. Have you considered ...

Gary. Have you considered other halogens besides chlorine, such as iodine?  Here is a link to a very good summary of water disinfection options, that includes information on iodine and iodine resins:  https://academic.oup.com/cid/article/34/3/355/388050   

i believe someone commented tablets are not sustainable and/or do not work.  No disinfectant is perfect.  Each has advantages and disadvantages.  A multiple barrier approach is advisable.  For example, while parasitic cysts are more resistant to halogens than bacteria, and to a lesser extend viruses, filtration can be very effective at cyst reduction in combination with halogen applications.  Keep in mind that a chlorinated water system is not free of bacteria, as evidenced by heterotrophic plate count (HPC) levels in public water distribution systems.