Can't speak to the Hydrofarm, but on my Herpstat I keep the probe on the flex of my middle tub (of 3) and keep digital thermometers in all tubs. I check them daily.

So far, so good.

I will probably buy a Hydrofarm soon. It never hurts to have an extra one for emergencies, or for that snake you didn't plan on bringing home and need to set up a tub for