Actually, the water is what provides the humidity, the PG is not a catalyst so much as a "regulator". If you can keep about 70% without PG all the power to ya. I choose the 50/50 blend to keep it simple, and to help prevent bacteria/mold etc. I know that you are well learned on this subject Rick, it was just the choice of words that I am commenting on. :) BTW, that is the FIST time that I EVER used a typed smiley face. It didn't do much for me....