I have been checking the thermometer on the vivarium more often recently as the temperature outside has dropped a bit and I have noticed the temperature has not been very stable as it can range from around 22 degrees to 30 (one point noticed it got to 34 degrees). Is this common and unavoidable or is there something I can do to prevent the drastic increase and decrease in temperature. The thermostat sensor is under the substrate.
What thermostat and thermometer are you using? Also you say the stay prob is under the substrate,are both your stat and thermometer prob together? Is it a heat mat you are using?
I am using a Microclimate Ministat 100 and I don't know what particular brand the thermometer is. Yes both the stat and the thermometer probe are together and yes I am using a heat mat.
I found the mini stat 100 I have has a big range and they are hard to get stable temps so I set it so it turns off at 29, the temps do drop bellow 28 before it turns on but the temp doesn't go above 30. In my other viv I have a habitstat mat stat that I find easier to use and more stable.
As mentioned the microclimate does have quite a range with the temps, double check your probes haven't been knocked. One of mine is really sensitive and if it gets knocked it sends the temps funny.