Hi Wizard! I think we have the issue boiled down to two possibilities:

1) My hypothesis that there is an organism in the water causing the irritation. If this is true, it may be possible to eliminate the problem by an environmentally-sensitive cleaning method, which is why I suggested the diluted vinegar scrubs.

2) Your hypothesis that Mother Nature has altered the chemical composition of the water. This may have to do with the fire, or it is possible that She has tapped a subterranean vein of some mineral compound which causes irritation to human skin. In this case, there is nothing we humans can do but wait for Mother Nature to cleanse Herself.

I live in Northern California. I have soaked in quite a few hot springs over the years, including an occasional visit to Deep Creek, but I have never had any hot springs-related dermatology problems until last winter's rash. I'm hoping to come down for a visit sometime in the next month or so. If I get down to the pools and find Wizard and his Munchkins scrubbing the walls with vinegar solution, I'll be delighted to contribute some elbow grease. Otherwise, I'll be the guy rubbing lemon juice all over himself.

Enjoy your soaking!