Enhanced Fluval P Series Submersible Aquarium Heater for 15 Gallon Tanks Review

Does not maintain a constant temperature. It was in a 6 gallon tank with about 5 gallons of water and the temp was everywhere. It got too hot. Had to replace it

Parts work as described. Although I wish I could control or regulate the temperature, the product still works and keeps my 3 gallon tank warm. Recommended for 3 gallons or less.

This keeps my 2.5 gallon Beta Tank at around 76-77.5 degrees depending on the temperature in my house while I work with a pellet stove. The Beta Fish seems happier and works much better than the old 10 watt heater I had.

Doesn't hold enough temperature on a 10g nano reef cube. Assuming the water is moving enough that it increases heat loss, you need to increase the size if possible. Maybe good for low flow freshwater tanks.

I recently purchased this heater for my 5 gallon hospital aquarium. It was placed within 3 inches of the moderately flowing filter water stream. The temperature of the tank constantly fluctuates between 76 and 82 degrees over a 24-hour period. (The room temperature was 72-75 degrees.) He continued to work in this way for a week. Fluctuating water temperatures stress your fish and make them ill. I would not recommend using this heater model.

Bought to replace an old heater that no longer works. Since Fluval is a decent brand I was hoping it would be a good heater but this is disappointing. It keeps our 5 gallon tank at just under 75 degrees, and our house is usually in the 60's-70's. I was hoping for more, around 78 for our Betta, but the temperature can't be regulated and that's the way it is. Our Betta is sick right now (because of the temperature difference? Maybe it has nothing to do with it) and I'm sad that he has to freeze…