Pseudomonas is a really common bacteria. This theory may have some credability since it has been documented in other warm water environments. I have not been affected by this rash at all, probably because I like to jump from the crab cooker into the icy cold creek.
I would not recomend dumping anything into the water but, common household bleach kills bacteria quickly and dissapates rapidly in the natural enviroment with sunlight exposure. I used to use it to clean out my old well when the algea growth became thick. I would let a day pass and then use the water for drinking and cooking with no ill effects. A cup or two did the trick. The current owners of this well dont do this because there are frogs living in there and they have another water source that is sealed.
Since the hotsprings is a natural ecosystem, I believe it should be left as it is. We as humans tend to alter mother earth to suit our needs way too much. I do like DCR's natural way of dealing with the problem without affecting the natural environment. Bleach kills all bacteria and frogs too!
P.S. Its raining!