Hermann tortoise heating probe mistake fix

A probe placed too close to the heat source is one of the most common — and most dangerous — mistakes in tortoise keeping. If the probe was reading 28°C but the cool end of the enclosure was actually 15°C, your Hermann would have entered hibernation in a body state that wasn't safe for it. Getting heating and UV lighting right is genuinely the single most important factor in reptile health — metabolic bone disease, respiratory infections, and botched hibernations all trace back to temperature or lighting errors. So let's sort this properly: what size is your enclosure, what heat source are you currently using, and where exactly was the probe sitting?

I'm glad she's recovering — that's a relief. The problem is clear: a probe 20cm from a 100W basking bulb is going to read artificially high. It's capturing radiant heat from the lamp, not the actual ambient air temperature your tortoise is living in. For an adult Hermann on a 120x60cm table, you need accurate readings at three points: the basking spot directly under the bulb (should be 32–35°C), the cool end ambient (22–25°C), and ideally overnight temperatures too. One probe near the heat source tells you almost nothing useful. What are you currently using as a thermostat — or are you running the bulb without one?

Running without a thermostat is genuinely risky — ambient temperature in the room will shift the basking zone significantly between seasons, and you won't catch it until something goes wrong again. And kit UV tubes are almost always inadequate for tortoises; Hermann's need a UV index of around 3–4 in the basking zone, which typically means a T5 HO tube like the Arcadia 12% Forest or the Zoo Med Reptisun 10.0 T5. But the immediate fix I'd focus on first is your temperature monitoring. I'd recommend the Inkbird IBS-TH2 — it's a small wireless sensor you can place at cool-end substrate level, away from any heat source, and it logs readings to your phone so you can see overnight drops as well as daytime highs. It's accurate to ±0.3°C, costs around £15 on Amazon UK, and takes the guesswork out entirely. You'd use it alongside a separate thermostat on your basking bulb rather than instead of one.

Exactly right — the Inkbird monitors and alerts you, the thermostat controls the output. For a basking bulb you need a dimming thermostat, not an on/off type. On/off thermostats cause bulbs to flash on and off which shortens their life and annoys tortoises. The Microclimate Evo Lite is the one I'd point you to — it's specifically designed for dimming incandescent and halogen heat sources, it's reliable, widely used by tortoise keepers in the UK, and it runs about £55 on Amazon UK. Set the thermostat probe at basking-spot height directly under the lamp, and place your Inkbird sensor at the cool end at substrate level. That way you have genuine control at one end and genuine ambient data at the other. Once those two things are sorted we can look at upgrading your UV properly.

Yes — and the good news is the Inkbird makes this straightforward. In the six weeks before hibernation, use the app logging to confirm her enclosure is hitting the right temperatures consistently, not just spot-checking. More importantly, the decision to hibernate should be based on her weight-to-length ratio using the Jackson ratio chart, not just calendar date. Your vet can advise on that specifically given her history this year. During the wind-down period, reduce temperatures gradually rather than abruptly, and keep the Inkbird in the hibernation box itself so you can monitor throughout — you want 4–8°C, steady, with no spikes above 10°C. If it drifts outside that range you'll get an alert on your phone before any damage is done.