The most important thing is to have at least one, separately purchased, CALIBRATED thermometer AND a salt tested humidty gauge in your bator.could you do a link to the youtube video please? I also have an incuview and a hovabator 1588. I had great hatch rates at the beginning of the spring but as the summer went on it got worse in both. I'm guessing the rain, humidity and air pressure had a lot to o with that. as well as young hens.
Did/do you have these.
I repeat I do not recommend following the advice/ways this person ran his bator.