Review on UPETTOOLS Submersible Aquarium Heater - Adjustable Thermostat for 🐠 3~120 Gallon Tanks | Temperature Controller 50W/100W/250W/300W/500W | 2 Suction Cups by Andrea Ellis

I bought this unit because I thought it would keep my 60 gallon temperature stable. Tank with African cichlids. It is installed horizontally in the water flow. Worked fine for the first week. Then I noticed that the temperature in the tank was slowly rising. Checked the dial to make sure it was "set" to 81F. Set them back to 79 F. The tank temperature continued to rise day by day. Unplugged that heater and plugged the old immersion heater back in and the temp went back to 80F in the tank and stayed there. Tested this heater in a 10 gram spare tank to see if the temp would continue to rise when set to 79F. She went up to 92 F over the next 2 days. Yes it's a big heater for 10g. But showed me it would cook my Africans. If you value your fish I do not recommend this heater.