OrlushySubmersible Aquarium Heater100W/150W/200W/300W Fish Tahk Heater with Adjust Knob Thermostat 2 Suction Cups and Free Thermometer Suitable for Marine Saltwater and Freshwater

Just today after 3 months , this heater killed 9 of my 10 fishes,The heater should automatically turn off after temp reachs 27.2 degrees, over the time the automatic off circuit did not work it literally boiled my fish and electrocuted them .

This product is rated and priced well. The heater is fully adjustable and capable of incremental adjustments. It also comes with an included digital thermometer to get your tank to the desired temp. It works great! I have fancy goldfish and keep my house cool so I wanted a heater to keep the tank at a constant temp so my fish stay healthy. I am very pleased with the construction and options. The digital thermometer is around a $16 value from what I saw at the pet store so this combo was a great deal! The instructions were easy to follow as well.

Nice looking, solid unit. 100W works well in my 20g tank. Tank is in a coldish bedroom and it brought up the temp ~15 degrees F quickly. The separate temp gauge is really handy, almost worth the price alone. Probably will order another unit soon to replace an old one on another tank.(Update - I still like the heater but I think the separate temp gauge isn't accurate - reads higher than two other units I tried)

It heats the water to 45C (110F) in 10 minutes and keeps heating until boiling. It’s so hot causing the protection mesh deformed. Very unsafe. Wondering who gave them the approval.

It works great, easy to use and seems to be very resistant.I recommend to start by 3 degrees less and follow the thermometer, raise little by little to your desired temperature. The temperature settings are not 100% accurate.I like that it is black and blends in easily.