Mine was originally a still air and I had a few decent hatches but not what I was looking for. I ordered the forced air conversion kit for it but was still getting hot and cold spots all over the incubator. Hatches got even worse. I simply mounted a small computer fan to the top blowing catty corner around the inside and now I have a constant temperature through out. I also added more ventilation holes I can open when needed.
Once I completed the modifications, I turned the thing on and ran it for about 2 months playing with the temp. while removing plugs in the vent holes. All the time adding different amounts of water and watching the humidity. Once I learned what it took to keep a stable atmosphere inside I started having 85-90% hatches. Learning your incubator before you try to hatch is probably the most important thing anybody can do.
Good luck with whatever you decide to do.
