Hey, I built my own incubator and I was wondering what is the temp you have set on your thermostat?

It is my goal to reach 89 degrees and I wanted to make sure that the temp of the tub (where the eggs will go) needs to be at 89 degrees, not the average temp of the incubator itself, right?

Sorry, I am new at this and expect my very first clutch soon.

Thanks.