Review on 🐠 Upgraded YukiHalu Small Size Submersible Aquarium Heater | Mini Fish Tank Heater 50W/100W with Built-in Thermometer, External Temperature Controller | Dual LED Temperature Display | Ideal for Fish & Turtles by Jill Bell

I like the compact 25w bulb version of this brand for my tail tank so I ordered this 100w version but the thermostat is off at least 5F. I had to set it to 86F to get to 80F in my 13 gallon tank, so it doesn't give me confidence that it won't suddenly increase the temp on its own when the ambient temp isn't that low. It seems to be holding the set temperature although the +5F reading is wrong so it could be a calibration issue and if so it would be nice to be able to recalibrate.