The problem with the temperature increasing during the day is do with the outside weather. I have my incubators set on 99.5 and sometimes during the day they go up to 101 but i try to watch my temps and then at night it stays at 99.5. To increase the humidity in the styrofoam incubator is 2 add sponge in it. I have used sponges like the one used to wash dishes like at Dollar Store or Wa-mart and let it soak up under running water and everytime the sponge looks dry, just pour water over the sponge just enough to get it damp. It should keep the humidity up, if it needs to be higher just get a bigger sponge, its no different then the sponges that is used in the cabinet incubators.