Glass bulb vs digital... which to believe?!

[dpenning]

I have a brinsea 20 that has a glass bulb thermometer. It holds temp very steady at just a smidge over 99*. My first batch I had two hatch out of 14 that were fertile. Many were late quitters. The two that hatched hatched early.

I put in a humidity gauge that also has a temp reading. It shows 103*!! Since the two that hatched came a couple of days early should I believe the digital and lower the temp on my second batch? They have been in 4 days.

 

[SunHwaKwon]

What kind of glass bulb is it? Can you put it in ice with a bit of water to make sure it is reading right?

The digital thermometers are not meant to be all that accurate since its not like lives depend on it. It should say on the pamphlet or packaging what the accuracy (probably + or - 3 degrees or something like that).