Orlushy25W Small Submersible Aquarium Heater, Constant Temperature Betta Fish Tank Heater of 78℉for 1-6 Gallons Freshwater & Saltwater Tanks

I have two of these heaters for two separate tanks. My 5G heater works just fine, keeps it at a steady temp of 78-80, switches on & off perfectly fine on its own. My 6G on the other hand, it was faulty. At first it worked fine but then it switched to red & green on all the time. I was out of town for a few days and I came home to a temp of almost 100 degrees!! Insane. Thankfully I got a replacement heater and that one is doing way better so far. Even though I had a faulty one, I still give this 5 stars because not all of the heaters are faulty. If this changes though, I will update. But as of right now I really have no complaints! I would recommend!!

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.