Goodness, I bet you were going crazy! I think finding good thermometers that you can trust and know are accurate is probably the most frustrating part of incubating. Did you try to calibrate them? Search on this site, there are directions on how to do it. I have an extremely accurate thermometer that I could not use for the incubator. I placed it along with my probe thermometers on the counter for about 20 minutes and noted the temp. I repeated this in the fridge, and under my brooder light. I was able to determine that they were pretty close to the same temp (all within a degree). I then just ran my bator based on that. I did not allow myself to go crazy if I was not right at 99.5 (like I did on my first attempt at incubating,... LOL! I was a hot mess!). If my temp my anywhere from 98.5 to 101.5 I let things be. I have great hatches going with this. All of my chicks hatch on day 20 1/2 to day 21. So I know my temp is pretty much right on.