DCR, I am very interested in seeing Ph information on the water. The very small red bumps, itching and thier quick disappearence after a day or so seems to me to indicate irritation to the surface skin rather than infection. The fact that you found the condition was " non-existant " after the acid solution rinse certainly should tell us something. This year has been the driest one ( to date ) that I can remember in my times at the springs. I know the flows are affected and increased by rainfall. We have had dry years for the last few years. Maybe there is less fresh water entering the hot water system which might be increasing the level of other previously benign elements in the hot water and therefore changing the PH.