I also use the Hydor ETH and like it alot. Gets the heater out of the tank, and temperature stays dead-steady where you set it. I have no complaints at all with it.
Thanks, eliminating equipment is my goal. I have a 125 with 2 fluval 405s and I already ordered a uv sterilizer to put on one, will one 300w be enough or should I get 2?
There is always the possibility of equipment failure.
I only use the Hydor ETH heaters on my tanks that have canister filters. I really do like them and when they should fail, I will replace them with the same product (unlees another mfg. should decide to offer an external heater).
The thermostat will shut it off. I have shut off my filter for extended periods of time with the heater attached and still plugged in without a problem.
Also if its on a canister its still in contact with the water, unless its installed on the tube above the water line. So it would just heat the water to the set temp and shut off, also as mentioned they have over heat protection; and would shut off without water. I wish they made bigger ones.