First-time leo owner - struggling to keep temperature up

I got a beautiful tangerine from MM a few weeks ago, and am struggling to keep his terrarium warm enough.

I have a 20 gallon long tank with an 8 x 12 under tank heater that I have set to 90 degrees with the thermostat. The probe is set on top of the substrate (reptile carpet) near the gecko’s warm hide, so I think it gives a pretty good sense of the temperature.

For the first couple of weeks, it seemed to vacillate between 83 and 86 but lately it is struggling to get past 81. It has been really cold here, and the room temperature is about 68.

Other than cranking up the thermostat, what would you recommend for raising the temperature a bit? A lamp? A ceramic heater? Another heating pad on the side of the tank? All suggestions welcome!

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How are you measuring the temperature? If you’re using anything except an infrared thermometer it likely isn’t accurate. If you need to increase the temperatures I would recommend putting the probe in between the mat and the tank bottom and increasing the temperatures one degree per day until it reaches the desired temperature. If you have to get above 95 and it still isn’t keeping the top warm than other heating options might help. If you need another heat source you can either add another heat pad or a ceramic heat emitter. Either one would need it’s own thermostat.


I’m just using the probe that came with the thermostat, but can move it under the mat and see what that says.

I can also get an infrared thermometer.


An infrared thermometer is the only reliable way to check surface temperatures. So once you get one check the temperatures and see if you need to make any changes.


Yes and infrared thermometers are super nice to have compared to the probes :slight_smile:


You were right. I borrowed an infrared thermometer and found that the basking spot was actually too warm, so dialed back the heat mat a little and will continue to play with the temperature to make sure I’m hitting the sweet spot. Thanks!


Great! I’m glad it worked.


I’ve found that it was easiest to maintain a good temperature gradient when the ambient room temperature is in the low to mid 70sF. In conjunction with monitoring via the infrared thermometer, you can keep an eye on your new baby, and see if he spends all of his time at one end or the other (indicating he is too hot or cold), or if he varies between the two sides (indicating that he’s able to appropriately thermoregulate).

When my geckos are in tank enclosures & the ambient room temperature is too low, I have partially insulated the sides/back of the enclosure with styrofoam. Just be VERY careful not to create a fire hazard.

As an aside- welcome to the forum @vagab0ndella ! If you haven’t already, you can make a post in the Introduction section & show us pics of your new leo! We :heart: seeing everyone’s animals!


Thanks so much. I’ll hop over and introduce myself when I get a good photo of the little guy. In the meantime, the temperature gun helped me figure out something I couldn’t see, which was that the UTH had come “unstuck” on one side despite being brand new. I fixed that and things are looking better already.

The little dude is mostly spending time in his warm hide and his moist cave, and very rarely venturing to the cool side, so I’ll keep an eye on that. Thanks for the advice!