Placement of thermostat probes

[twisted poke]

I recently purchased and currently housing a ball in a 20G glass vivarium. As of now, I am using two UTHs with a cheap rheostat. It was less than ideal so I bought a couple of thermostats that arrived today. I plan on modifying the cage this weekend. My question involves the placement of the thermostat probes. I have been using this guide for setting up the vivarium:

http://ball-pythons.net/forums/showt...ass-tank-setup

According to the guide, the probes should be placed on top of the repticarpet, under the substrate. However, while researching thermostats on this forum, I noticed several people stating that the probe should be placed between the heater and the glass (outside the tank). I would think that if you put the probe between the heat pad and the tank that there would be a few degree difference between the temperature there and at the top of the substrate. Looking for suggestions on which is the preferable placement. The thermostat is a herpstat and I am using a bark substrate on top of repticarpet. Thanks for your insight.

[JLC]

I wouldn't use repticarpet at all...but that's just me.

I believe the best place for the probe is, indeed, on the outside of the enclosure, between the heat source and the glass. Yes, you will have a temperature difference between where you set the t-stat, and the ultimate temps reached above the glass. A little bit of tweaking with thermometers, and you'll get it set just right.

Why should the probe be placed there? Primarily, because if it is outside the enclosure, then there is absolutely NO risk of the snake moving the probe. If the probe gets moved off the heat source, the UTH will spike uncontrolled. And I don't know any really good way to secure a probe within an enclosure. Tape is out of the question, as the snake will inevitably find a way to get it stuck on himself. And if you glue it down, then cleaning and ordinary maintenance becomes a big headache. Also...at one point, I did have a t-stat probe inside an enclosure...and a rat merrily chewed through the cord while being ignored by my finicky snake.

[RichsBallPythons]

Always place probe on the UTH and or Flexwatt