Quick question for all you smart people out there (the more I read on here the more I realize I don't know!). I have an old KUHL forced air incubator with a big glass dome. It runs like a champ, but how do I add water to this thing (between day 18 - 21) w/o messing up the whole hatch? This glass dome doesn't have holes or plugs. I have to lift it in order to get a tube inside to add water. My concern is if humidity is low on like day 19 what should I do? ..... all I've read is DON'T OPEN, DON'T OPEN the lid.... so I'm thinking... yikes what do I do? Any words of wisdom?