Even if it's a 600 egg incubator it works pretty much the same way. I bought the 600 egg one last fall and used these instructions and it's working great. Started it up Sunday night. Set the eggs by Monday night. And no fluctuations of any kind. My only issue is the egg roller. They just don't seem to be rolling the way I like them too. The elderly man I bought it from used it since he bought it new and said he had a 90% to 95% hatch rate and he only used the old mercury thermometer (included) and never paid attention to the humidity. I attached a digital thermometer/humidity indicator in the front right in the center of the 3rd tray down. Is there something I can add that I can roll the eggs better?