There is clearly lots of debate on temps the problem I see with the top end is what if your thermometer is not accurate most inexpensive digital units have specs that claim it will be at least 2º of accurate over or under 95+2=97 and everybody will agree this is too warm. My suggestion is most say 90º so not hotter than 92º if you do not have a known accurate thermometer. I personally use 90º. The CHEs get very hot you should insure it cannot get the tub too hot of fall. Tubs suck in cool rooms for this reason.