I give my eggs a bath once a day in 32 oz of water and 1tsp of ACV. I read a lot about how a daily misting/cool-down really helped increase hatching numbers. Lots of people also talk about really low numbers of goslings hatching because of the tough shells. So, that is why I'm adding a touch of ACV, it has weakened the shells just enough to make it easier for the babies to hatch.
I have a similar incubator.....I really have been adding in a lot of water. I fill the bottom, along with doing my daily egg bath, and egg misting.
I still have 14 cooking in there and I hope to keep adding them as she is laying them. I have two eggs that will be going into lockdown in another day or two.