Review on 🐠 Uniclife Submersible Aquarium Heater with Electronic Thermostat - Preset for 5-50 Gallon Fish Tank, 25W/50W/100W/200W Options by Lindsay Siebert

. Your table telling you what size to get for what tank capacity is incomplete. They are designed for a specific tank size depending on how much ambient temperature rise you need. If your home is cold or gets a lot cooler in the colder months, a size they say may not work. Be sure to find out about the temperature in the room where your aquarium is located and what temperature you plan to heat the water to. Spot the difference and find another chart that lists the correct size based on both the temperature rise required and the size of the tank. One worked great in my 10 gallons to keep the roosterfish water at 80 degrees until the temp dropped and I had to switch my house to heat. I then had to rush in with a backup heater to get enough heat to keep my faucet safe until a more powerful heater came along.