Review on Tetra HT Submersible Aquarium Heater: Efficiently Regulate Temperature with Electronic Thermostat by Cindy Hardin

Warning! When I got this 2 months ago I noticed that the heater light went on and off when it was a warm day. I even disabled it once, thinking it shouldn't be enabled. I went to a matinee today and when I came back I lost 2 fish and my ghost shrimp. I have living plants and many of them have withered. Of course I control the light (on), control the temperature, it was almost 90°! The poor things are screwed up! ☹ I immediately took them all out, did a water change, the rest seems to be fine. The fact is that the thermostat in this heater failed and killed my fish. Very sad.