Best digital thermometer.

[Yzmasmom]

Thanks for all the tips.

I'm an idiot and didn't even think to use the search function in the forum. When I finally remembered, a couple people used one like this from Walmart. The probe goes on the hot spot and the unit goes on the cold side and measures that. Both temps with one unit.

But, there's no longer a probe inside the cold hut, so I guess if the cold side outside reads 82 to 83 I'd have to assume the hut would be about the same?
(The temps are wonky in the pics because the lids were off the tanks for a while and they cooled down.)