A very sad day

[FunkyRes]

All three of my little brother's '07 corns died today.
The cause - failure of a thermostat. They overheated.
When the thermostat failed, I don't know, but it did - and three little corns died as a result.
One thermostat controlled identical heat sources for multiple cages.

His '06 corn survived.

I'm now looking into a thermometer with a warning beep when the temperature gets to a specified level, there was a digital thermometer set up in the tanks but I don't know how often he checks them, he takes very good care of them but he has some learning disabilities etc. (his birth mother was a drug addict and tried to abort him by over dosing - he lived, but his brain was damaged - drugs are NOT a victimless crime) and may have not checked the thermometers as often as he should have.

Anyway - he is devastated. The heating pads were those ZooMed UTH - I guess this is positive proof that ZooMed do get too hot when not regulated. I may look into a brand that does not get as hot on full power in addition to thermometers that have a warning buzzer before he acquires new snakes.

He had a very beautiful reverse okeetee, a charcoal het amel, and a hypo het lavender.
This morning he went to check on them, two were dead and the third died in his hands.

Any recommendation on a thermometer with a good warning beep?
The thermostat was a BAH-1000 (several places sell identical thermostat under various re-branded names) - I'm going to make sure they go Helix next time, much more expensive but mine have been spot on perfect and I know they have some built in safeguards against over heating.