I have and old LG still air that I added an egg turner to and a computer fan for air circulation. 15 years ago, my neices and I were able to hatch about 80% of eggs shipped from Georgia to Washington State. I decided to try some quail keeping for eggs and fun. I pulled out the old LG, washed it down, disinfected, aired it out and started it up. I ordered a Thermo/hygrometer unit from an online source (commercial company not individual) and got the incubator stabilized and ordered some eggs. I noticed the whole time that I had temperature swings that were more than 2-3degrees + and - of 99.5F. A few days into the set, my morning check and the thermo read 158deg F and 99% humidity. I touched the eggs and they felt like they were at about the right temp. I know I am not a human thermometer but I can tell the difference between approx human body temp (99.5) and burned at 158. So I topped off the water to where it normally was and continued on. I went to the website and asked the supplier of the Thermo/hygro unit about this and the sent me a new one. New problem, the old unit and new unit can vary in readout by as much as 7deg F and 12% humidity. I bought a cheap liquid filled thermometer and it falls inbetween the two, not evenly. I set 12 eggs, one hatched, two pipped and quit, and not even a roll from the others. I ordered a new batch (24 from different seller) after I replaced the old wafer thermostat and element heater with a new progressive style digital electronic heater. I use heat sinks in the incubator to help keep and even heat, about 750 mls of water in more than one container place so they don't interfer with the egg turner or vent holes. The feed store was closing out incubators and got a great deal on a new LG 10300 and used that as a hatcher for this batch. I never really had to add water to it to keep the humidity up (according to the incubator read out). This time again, 1 hatch, 2 pipped and quit. The two quitters may have been too big to move inside the shell. Does anyone use a commercial humidifier/hygrometer unit to produce humidity and keep humidity level regulated? Which one? I leave vent holes open and don't drop the temperature for the hatch. I work longer shifts so I need a way to keep the humidity levels up in the older LG the way one of those units does. Any ideas?