
I used this heater in a 20 gallon NANO reef aquarium. It still works with no problems. It is controlled by an APEX controller and this controller acts as a backup. This device works great with APEX turning the power on and off when the heat needs to be turned on. Settings hold without problems. I assume that if the apex fails, the device will shut down at the set temperature. The included controller is very accurate. I checked the displayed temperature with a certified thermometer and it is normal. I'll be buying a few more to have on hand and for the few quarantine tanks I'm installing.

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