I hate to say it, but I just have an aquarium thermometer strip. Nothing fancy. You can judge by the roaches behavior too. If they're all at the top under the light, they're cold. If they're all hiding at the bottom, they're too warm.

Yeah, I prefer the food at one end, but there's not enough room. I just have too many. I have more than I thought ... realized when I cleaned them out. The cartons are actually somewhat heavy when you pick them up. Roaches on both sides. I'm guessing near 600, minus the nymphs. I'll sell some this summer.

I put the frass in our flower garden. Well, in the snow yesterday, ha ha! Makes the flowers bloom like crazy .