Review on High Performance Submersible Aquarium Heater with Auto Thermostat & LED Temperature Display - Ideal for Fish Tank Water by Christine Rowe

The heating worked perfectly at first. I set the temp to around 78°C and it kept the tank temp between 78 and 80. It's only been a month since I bought it, this morning I woke up and looked at my fish tank and noticed several fish swimming and acting upside down. strange. I went to the tank and felt that the glass inside was unusually warm. I looked at the digital thermometer that came with the heater and it read 99°. Then I notice that the light on the heater has gone on. I immediately tried turning the temp dial on the heater all the way down and the red light stayed on and never went off. Then I unplugged the heater and took it out of the tank. I removed the aquarium lid and added some ice packs to cool the water as I was concerned all my fish would die. I lowered the temperature to 84°C and the fish started swimming normally again. Unfortunately I lost two fish. The thermostat in the heater just failed after a month of use. This is bad quality. I'm glad I noticed this before I went to work otherwise I would have come home and all my fish would have been dead. I'm very disappointed because it's been a month now and Revain won't accept it or refund my money.