Fish Tank Aquarium Heater - Adjustable Temperature Submersible Thermostat Heater,25W/50W/100W/150W/200W/300W

I was in need of the heater as my old one broke. This works as a good option as it has a cheaper price and good reviews. It maintains it temperature after settled even though the temperature is 1-2 degrees off from the knob indicated temperature reading (I noticed all my previous heaters did that, so not surprisingly for me).

Worked well during the Texas freeze. I had three of this 300w units running in a 500 gallon outdoor tiled gunite pond and they kept the water above 45 or so. I had another floating heater, that helped bring the water up to 57 or so but the floating heater is useless IMO, it does not turn on unless the water gets to 35 or so. These ones work non-stop, it will never reach the 80F setting I have.I dont think this will be suitable for colder places. Suction cups are useless.

It just works on and off without reaching desire temperature for 4 months and then stops, not happy at all

Great fish tank heater. Works great. Be careful taking it out bc it gets very hot lol

Save your money, do not buy !The heater shattered and killed a $40 dollar fishPlease save yourself time and and money and buy a better heater with a digital display and adjustable settings

The temp knob is way off. I have my tank at 80* and the knob is set at much higher then it. I've been doing a no fish test run the past week after our beloved Betta passed from temps not staying at 78-80 which is why I bought this heater. It is small and works great in our 3.5 gal tank. It keeps it right at 80 and kicks on and off. I keep it on a corner of my bow front tank so not see looking right at it. The little fake plants it comes with are cute and feel pretty soft plastic so I've kept them in case I change everything out or add more to a tank later since I'm planing on a bigger tank later on.

Product came in the mail quick and works as it should. I don't use it in an aquarium. It's used to heat up saltwater for water changes. Probably about 5hrs a week. Works quick for 40 gallons of water

Updated review: I had surgery and was unable to return the item for a couple of weeks, so I just left them plugged, in the fish tanks, until I could get to it. Suddenly, I saw the lights on both were on, and the water was warm (very warm, as a matter of fact). So I adjusted the temperature on each and they now work as a charm. Have NO IDEA why it took about 2 weeks for them to start working, but it happened and I'm happy. Not returning anymore. From 1 to 3 starts because they didn't work immediately... Which doesn't make any sense whatsoever.Original review: Have a 2.5 gallon and a 1 gallon fish tanks, so I got 2 of the 25W ones that are recommended to a max of 7 gallons. At first I read afraid I was going to cook my fish, so I started on a lower temp. I've had the heaters in the tanks for almost 5 days now, but water temp has not increased, not even 1 degree!!! Even after I increased both to the max setting on day 2... Still nothing.