incubator temps

i have two thermometers - one in egg box (no eggs yet) and one underneath the egg box.

I have heat cable running in a descending spiral position taped to the sides of the cooler, no fan.

I had the heat cable taped in a UUUUU configuration around the walls of the cooler and it ran 89 and 90. I reconfigured it so it goes around and is taped around in 3 rows on each wall.

The problem now is thermometer under the egg box reads 86, and egg box runs 89. what different configurations/patterns do you guys use? (heat cable only). anyone just lay the heat cable on the floor of the inc?

does just the egg box have to be 89-90? or should the whole thing be that temp? thanks!

Without eggs, the temp inside the egg box and outside the egg box should be the same if it's had time to equalize. The temp inside the egg box is what's important, but you need to know why they're different. My guess is you have a heat gradient where the higher region of the incubator is warmer than the lower region (stating the obvious = heat rises). Do you have any kind of fan circulating the air in the incubator to keep the temps stable and equal in all regions?

Just reread your post and you don't have a fan - that will create uneven hot spots in the inc.

I don't have a ton of concern for the temp in the corner of the incubator, or the upper/lower 3 inches. I am most concerned with the temp where the eggs actually are. Inside the box.

There is typically a temp gradient top to bottom, inside/outside the egg box, etc. Depending on your setup, you can see lots of variability, but actual egg temp is most important : )

I don't think the configuration is going to matter as much as not having a fan. I would never run an incubator without a fan. They cost $10 and you can wire them to an old cell phone charge. The fan can mean the difference between healthy babies and deformed babies.

Second that, we use small computer fans to circulate the air in our incubators.

i got a fan. now i have a one - one and a half degree difference between egg box and floor of inc. thanks guys!