I have a sponge and I just added more water because the windows were drying up and I have to keep it covered with a towel heat stays stable better that way. I went out to let the chicks out for a couple of hours when I came back in Humidity was down to 40 but temp was good.I go for 60-70. That's when the viewing window starts to get condensation in the corners but isn't fogged up. How often have you adding water during incubation? Do you have a sponge in there or water the incubator wells?