I don't trust chlorine in my drinking water, tanks, or anywhere else... it belongs in pools and for bleaching white clothes only! I myself would NEVER put any chlorine tablets or chlorine drops of any kind into my fresh water holding tanks... I flush them out frequently with filtered fresh water and have never had the slime or bacterial growth... as long as the incoming water supply is filtered of any particulates and most of the phosphates (food for bacteria and slime) there will be no algal slime or nasties... been doing this for marine aquariums most my life... only other pure water supply is reverse osmosis and that is not doable on our boats... huge energy/water waste... Chlorine is really not good for your health as I said... can't post the link due to my posting privilage but here is a good read:
internethealthlibrary DOT com/Environmental-Health/Chlorine-and-cancer DOT htm
I agree that Chlorine in the above dilutions is not healthy for drinking, but for cleaning and sanitizing it is not harmful. I think there are very few public water sources that will not contain chlorine.