Can this incubator be trusted?

[J.Vandegrift]

A Hovabator with the wafer thermostat removed, the top vent hole blocked, and connected to a Herpstat thermostat, is what I'm using this year.

I have it set up with substrateless incubation, and I fit FIVE clutches in there. Not small ones, either. I put the water directly in the included plastic base, and put the light grid over top of that--no separate containers.
3 clutches have hatched out in that setup so far, and not a single loss of any egg in there.

Nice. The herpstat is the key. As long as you get that wafer out of there it should be pretty reliable. Then it's pretty much just a styrofoam cooler and a heat source.