I have the thermostat probe inside an empty tub on one rack(8-shelf), taped over the flexwatt. Helix t-stat is set at 94, hotspot reads 94. I have a Herpstat 2 on my 6-shelf adult rack. It is set at 85/80 for 16 hours, and then is bumped back up to 94/84 for the remaining time. They are breeding just fine.