I've had it with 500R. Just checked Choco/Inez's that's been running three weeks (on this particular set up of mats, placements, etc.) and it had a high of 99F! (and a low of 75.6) There's no way to know what's going on without a reliable max/min thermometer...
Meanwhile, in Zee's setup where I pulled the 500R and put in the Herpstat, it's varied from 80.1 to 82.2.
Maizey with the new Herpstat ND has ranged from 81.0 to 83.3.
Nanci