I have a Little Giant still-air incubator and an older still-air incubator (don't know brand or model) that I use to incubate. I purchased a new thermometer (glass incubator thermometer) and put it in the LG with my other thermometer (which I have found very accurate) and calibrated. The newer thermometer read 96* whenever the other read 99.5*, so I wrote that down and kept the incubator at the 96* mark on the new thermometer. I recently had a lot of my eggs die early in the egg. I figured it must be a temperature problem, so I calibrated the new thermometer in a mixture crushed ice and water. It turned out to be one degree off, so I had been freezing the chicks in whichever incubator that one was in (which I feel horrible about.) I was unable to calibrate the old thermometer because it doesn't reach 35*, so I put it in the bottom of my older incubator with the new thermometer. They both read the same thing, which was completely different than what had been going on earlier. I have another batch of eggs in the LG, so I put the older thermometer in their and kept it around 99.5*. 4 out of the 6 fertile ones we're thriving well. I decided to put the new one in there also (older one on left, newer one in right, both on top of eggs in turner) and see. Well, the older one reads 99.5*, while the new one reads 93*. Which one am I supposed to follow? Thanks.