My 25 dollar Tempgun reads about 4 degrees lower than the Accurite probe on the warm side over the UTH. Even when I place it into the substrate right where the other probes are, it's always ~ 4-5 degrees lower.

I'm using a less expensive Hydrofarm thermostat for now <sigh> and that reads very close to what the Accurite says as well.

I'm just trying to get the temps as accurate as I can and it's driving me nuts when the tempgun says something completely different.

What do I trust? Digital thermometer with probe over the center of the UTH, or the tempgun?

Thanks for reading.