im getting 99 high and 91 lows in my homemade incubator

[dionegrey]

Is 91 to low for the lows in the incubator and if so how to adjust that with running a thermastat that is used in hot water heaters

 

[ChickenWing]

yes it will be too low as it will give you an average temp of about 95. I am not familiar with how to adjust those.

 

[AmyLynn2374]

Is 91 to low for the lows in the incubator and if so how to adjust that with running a thermastat that is used in hot water heaters

I can say, yes 91 is wayyyyyyy too low for temps (at least for chicken eggs). If your bator is still air (with no fan) it should average 101-102F (measured at top of eggs,) if it is forced air (with fan) it should average 99.5F. At 91 degrees chances are you will not have hatchers and if you did the chances that they would have health/development issues (if they make it at all) is monumental.