You can put water bottles in to help with humidity.
Also don't check on the too much. Leave them be as much as possible.
90 is perfectly OK for them to incubate at. I keep mine between 89-90.
And as far as adding water, add accordingly to what you feel is necessary.
Do u have a thermometer and hygrometer in with the eggs to get an accurate reading AT the eggs? That way you know if the humidity and temperature are correct and where you want them. Thats what I do. Just a thought.

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