I picked-up a still air incubator last week. I understand the temp of 101.9 for a still air and I understand to turn them 3 times a day. I'm starting to understand candling but about the humidity? how do you check and control it?
Walmart carries a very reasonable thermometer/hydrometer in their larger stores and online for like 6 bucks. Get two and check the accuracy when you get them. Make sure to note any - or + changes right on the thing with a sharpie marker, so you don't confuse the two. This is the easiest way to track the humidity which is so important to hatching eggs.