Is my heater just broken or undersized?
I posted this elsewhere on another forum, but wanted a bit more feedback. I have a Marina 360 (2.65 gallons). I've been looking for heaters and settled on a 25 Watt Marina C - 25. It's one of those designed to heat the water to 78 Fahrenheit. No option to change temperature. I like it because it fits in the filter compartment in the tank already providing a clean look.
Unfortunately, it's only warming the water maybe 4 degrees above ambient. House temp is a constant 70 and I'm only getting the water to about 74. Last night temperature dropped to 68, and water this morning was about 73.
Has this heater really not got enough juice to warm this water, is it not calibrated correctly from the factory, or just plain broken?
I've seen people using 50 watts on 5 and 10 gallon tanks. This is over the recommendation of 3-5 watts per gallon to. So what gives here?
And if it isn't working, can someone recommend a heater that would fit in the Marina's filter area. About 5 3/8 inches.