Incubator Warehouse does not make it, GQF makes it. You can e-mail them at email@example.com
My guess is that your main problem is the temperature of that bathroom. The heater on an incubator is not tremendously powerful. The recommendation is that the incubator be in a room that is at least 70 degrees so it can keep up. It’s just not made for fluctuating temperatures of 52 to 62 degrees. GQF’s write-up says it can handle temps of 60 but that’s cutting it really close.
I have a Hovabator 1588 and it has no problems holding a steady temperature but it’s in a room above 70 degrees. In your bathroom it’s not likely to be hit with direct sunlight which can cause problems, but is it where a draft from a vent is hitting it or maybe do you change the temperature in there pretty drastically by opening the door? Any incubator does better if it is in a room with fairly consistent temperatures above 70, is out of drafts, and is not in direct sunlight.
That incubator has the same type of reservoirs for water as my 1588. What controls humidity is water surface area. How deep the water is does not matter except for how fast that reservoir runs dry. How much time are you giving it to stabilize humidity? If you spill a little water the humidity will spike until that water dries up. Patience may be required on your part.
There is another part to this. How constant is the moisture content of the air going in? I’ve seen mine vary from 17% to 31% with no water inside at all. With one certain reservoir filled it may vary from around 30% to over 45%. The difference is due to the humidity of the air going in although the temperature of the air going in can play a part too.
Never blindly trust any instrument, thermometer or hygrometer, unless you know it has been calibrated. I don’t care if it comes from the best incubator company in the world, the ones that come with the incubators just aren’t that reliable, let alone any from other sources. Here are some articles that might help you with that.
Calibrate a Thermometer
Rebel’s Thermometer Calibration
Rebel’s Hygrometer Calibration
We are not chickens or broody hens. Broody hens usually do a better job of incubating eggs than the professionals that may hatch 1,000,000 chicks a week, every week. The ideal condition for a hen is that she lays an egg a day for maybe two weeks before she starts incubating them. That nest should be in the shade so the sun is not heating and cooling them that much, plus if it is on the ground the temperature and humidity level doesn’t fluctuate nearly as much as you might think. Even in a lot of our coops the temperature and humidity in the nest doesn’t fluctuate dramatically, though each coop is different. A broody hen does have some control over humidity too. Some people have put hygrometers under them to check.
I’ve seen a broody hen come off the nest two times a day and stay off over an hour each time in the heat of summer. In cooler weather once a day for about 15 minutes might be more normal. Broody hens are aware of those things. Instantaneous air temperature isn’t all that important anyway. The egg is a lot denser than the air so it takes it a lot longer to heat up and cool down inside where the chick is than you’d think.
Incubating eggs is not knew. The ancient Egyptians were doing it in the times of the pharaohs. People have a lot of experience incubating eggs and there have been a lot of studies on what procedures give you the best chance for a successful hatch. It’s still a lot of art instead of science. The professionals using incubators that may hold as many as 120,000 eggs at a time still have to tweak each incubator to get to the maximum hatch rate. The guidelines they have given us give you the best chance of a good hatch, but many of us violate some of those guidelines all the time and usually get a pretty good hatch. The more you violate the guidelines the worse your chances are but the eggs are usually pretty tough. You don’t have to be perfect to get eggs to hatch, but it helps to not wander too far from the guidelines for too long. Just do the best you can and treat the first incubation as a learning curve.