My incubator is a Farm Innovators from Tractor Supply and is forced air. I have the IncuTherm digital Thermometer/Hydrometer. I am not sure how to calibrate it but I have put several thermometers into the incubator and they all seem to be within a degree or two. I try to keep the temp at 99.5 for the duration but it sometimes fluctuates as high as 102. The humidity is my biggest problem to regulate I try to keep it in the high 70's until just before hatch but it tends to stay around 68 to 70 this last time it has gotten up to around 80 while they are actually hatching. I haven't done the "eggtopsies" yet but will on the ones that don't make it, although I am not sure how to interpret the results. As stated before though I have peeled away one that the chick "looks" fine but is obviously dead in the egg.