rabbut
I don't bite, all that often...
The Ehiems do have a good reputation, and don't get me wrong, they will have a fiail safe of sorts. The problem is that it would be difficult to fit the thermostat near the element, without it clicking the elemet off before the water is up to temp, because of the way water will flow around them. The thermostats will be fitted to the out or in pipe of the filter, hense if something happened to empty the canister, the thermostat would be exposed to the air of the room, and would thus measure the ambient room temp, rather than the water in the filter.
If the heaters do fail in "on", then it won't boil, as the heaters aren't powerful enough. However, the temp will easily rise to 50 centigrade, possible higher, and that is as good as boiling as far as the fish are conserned.
If the heaters do fail in "on", then it won't boil, as the heaters aren't powerful enough. However, the temp will easily rise to 50 centigrade, possible higher, and that is as good as boiling as far as the fish are conserned.