Review on 🐠 Penn-Plax 75-Watt Fully Submersible Aquarium Heater: Precise 1 Degree Accuracy - Ideal for Up to 15 Gallon Tanks by Atiyya Green

First of all, I recommend reading the 3-star review of March 7, 2018. I have a 25W heater in a 5.5G tank. As the reviewer recommends, I keep the room temperature fairly constant. I went through 4 heaters over the course of a month: one kept turning higher and higher until it cooked my fish when I had it there before testing the heater, another warned not to use with the light on. Tank and readings bounced all over the place, kept the third one as a spare as it was too bulky, finally stumbled upon this one which I've had for over a month now. This heater is very stable, I set it to heat the tank to 78.8F before turning off and it constantly waits for the tank to cool to 78.3F and then turns it back on and reheats the tank to 78.8°F and again. The only thing to do at first is to check the heater with a thermometer as mine was off the scale by 2 degrees but after equalizing it works fine. For less than $12, it's steel, it's precise, it fits well, it has a good chord, the adjustment works well, the heat gauge is big enough to see, and it fits nicely between the two hob and the corner of the tank. Finally a heater.