I would make sure there is some sort of thermostat with a probe hooked up to your incubator. What type of temp gun is it? Does it measure surface temperatures or air temperatures? No matter what you have that will show you what the current temperature is, you need something to control the temperature. A helpful feature that some thermostats have is screen that shows the highest and lowest temperature so you know if you've had a temperature spike while you weren't around. I'm not sure how much you are willing to spend on a thermostat, but I'm sure there is an affordable one that will get the job done.