Review on 🐠 Bnzaq Submersible Fish Tank Aquarium Heater - Adjustable Temperature Thermostat Heater, 25W/50W/100W/150W/200W/300W by Eliza Porter

. Used the heater for about 9 days. It turns on and off and keeps the water temperature. However, it works around two to three degrees of heat. I have a separate thermometer in the tank to make sure the heater is working properly. (If I want 78°F, I set the heater to around 74-76.) As other reviewers have mentioned, the red knob is difficult to adjust once installed. very narrow in a curve, ok for the price.