Usually, if there is condensation on the window, the humidity is considered too high because when the first chick hatches, it will rise automatically anyway. That's when you'd open up all air holes to let it out. Coloring the water is a great idea, for sure, though in my old bator, I colored the underside of the plastic tray with red or blue magic marker so I could see where the channels were. Otherwise, it sure is hard to see, isn't it?
I have the Genesis ready to go and the eggs coming up to near room temp (the bsmt is about 55* where I store them prior to hatching). This will be a great test of the incubator. I'm calibrating the hygro and that should be finished by 10 p.m. tonight. That is easy to do, just a pile of wet salt in an open container and the hygro near it in a closed ziplock bag. By 8-10 hours, it should read 75%. If not, you know how much it's off by and adjust your readings accordingly. Will have to get out my big sponges later on or I may get some new ones, or just might soak these in Oxine water to be sure they're okay, even though I do that after every hatch.
I dont know why I call it a hydrometer... Thank you for the information on testing it. I wondered about that which is why I used a homemade one with an accurate thermometer.