Thank you for responding. Yes, they are identical and purchased at same time. Both one year ago. We looked them over carefully regarding the fit and do not see any issues. Just doesn't make sense for such a difference.
We have 2 Brinsea Mini Advance incubators in our classroom. 7 chicken eggs in each. Last year and this year we are seeing the same issue with the incubators. One unit shows a lot of humidity without needing to often lift the lid and put in more water often. The other unit does not show any...