Is a 150 watt heater too powerful for a 20 gal tank?

I'm downsizing and trying to figure out which items I can still use. I've got a 150 watt Aqueon heater that I had in my old 45-gallon. Is this just too powerful for a 20-gallon? Room temperature can get down to around 60 degrees at night in winter, but can also get randomly up to over 80 degrees if we have a heat wave (it has gone up into 90's in January here). I want to keep the Endler's between 74 and 76 degrees.

Thanks for your input!
I'd like to know this as well. Now that the temp is dropping I have to heat my 20 gallon & I also have an Aqueon 150 watt. I just installed it yesterday, haven't turned it on yet.

While I know it is way more than this tank needs, I expect it is only a problem if the heater malfunctions, right? I hope?
It will be fine if it has temp control. you should also check how long it takes to rise the water temp. u don't want to do it too fast.
Last edited:
You would not want to stick a 150w heater in a 5 gallon tank, or a 400w heater in a 20 gallon, it would raise the temperature to fast. But a 150w heater is not too much for a 20 gallon.
5F per gallon= 100g. Should be fine. Probably can keep on lower setting.

Not sure what you are saying. The setting should be at the temperature that the user wants for his tank. You wouldn't set the temp at 70 if you wanted the tank at 78° no matter how quick or slow the heater works in the end the desired result should be the temp that is set.

FWIW I have a 150w in my 20 long and its just fine.

Random Great Thread

Latest threads

Top Bottom