“Chlorine is indeed THE best sanitizing agent, especially for drinking water...but it is FAR from being natural”
My bad... sort of:
[Search results] “Chlorine is in group 17 of periodic table, also called the halogens, and is not found as the element in nature - only as a compound. The most common of these being salt, or sodium chloride, and the potassium compounds sylvite (or potassium chloride) and carnallite (potassium magnesium chloride hexahydrate).”
I was thinking element.
And you were right...."elemental" chlorine IS a great sanitizing agent. It's just that the elemental form doesn't exist in nature (other than in volcanic gases). And as a chemist I tend to be a bit anal about chemical fine points.