Totally agree with Longranger! I'm in the middle of my first hatch with my King Suro, and although it's been great at holding temps and humidity steady, I suspect my temperature was too low for this hatch. I assumed it'd be correct right out of the box, so I didn't calibrate it.
I set 17 duck eggs, and have had 10 hatch as of today, Day 29, with several more in process. So the hatch rate I think will be good, but the late hatch leads me to believe the 99.5 F I was reading throughout the incubation wasn't quite right. Oh well, that's what test hatches are for!
I've just ordered a
Brinsea Spot Check thermometer (which comes highly recommended for reliability from this board), and I'll calibrate it before I set my next batch. I'm also going to double check the humidity. I have an Accurite which I'll calibrate, then pop it into the Suro after this hatch to see how it reads against it.
My very limited experience with this incubator is that it's extremely steady and reliable at holding settings, so if you're having disappointing hatches in it, I'd suspect either your settings being off, or another cause.
Also, I remember reading from another poster here that when she switched the display read out from Celsius to Farenheit, it caused the incubator to run at a slightly lower temperature, so that might be at play here, too.