Review on YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks by Lora Schnabel

This is an attractive unit that’s easy to set up. The temp never stays stable though so I set the temp lower than what I’d like so I don’t kill the fish. When I initially set it for 73 degrees it would fluctuate between 72 and 78 degrees. At least that’s what the controller shows - I don’t have a separate thermometer to measure the actual temp of the water.