I poked around and I couldn't find this specific piece of info so I figured I'd ask before I did something really wrong.

I've got two 10 gallon tanks with juveniles in them, UTH in each. I've currently only got one heat lamp with a ceramic heater, am getting another ASAP along with a thermostat. For the next couple of days, though, this is what I have to work with.

Each tank has a digital thermometer/Hygrometer from Wal-Mart with an outdoor temp probe (http://www.walmart.com/ip/Acu-Rite-I...mometer/896347). I need help placing the outdoor probe. First I affixed it to the hot side of my cage, inside near the base. I was getting a temp about 2-3 degrees warmer than the cool side (Hot 85, cool 82). Then I thought that maybe I should be reading my hot spot above the UTH so I moved it to right above it below my carpet. 109 degrees! That freaked me out since it seems WAY too hot, but then I got to thinking that the carpet's probably insulating it a lot. I know that when I get the Thermostat I'll be placing it underneath the UTH, but for now where should I be measuring from with my two thermometers?