I have to mention again that an empty bator is very unstable. You need
mass inside it to regulate the temp.
The Genesis is good because it has a pulse control that turns the heater on
in pulses, not on/off. Some bators, like the Little Giant (of which I like), have
heating elements that turn on, heat up like crazy, then turn off. The effect
is a greater temp swing. By adding lots of eggs, water bottles, even rocks,
you help prevent that swing. It just takes much longer to come to temp or
adjust. IMO you should run a bator for 3 days or more before placing eggs
in it, especially when having to adjust things.