Can a heater be too big?

[Brieninsac]

I want to replace a 50w heater in one of my 10-gal. QTs. I'd like to get a titanium Finnex since I have a few of those and really like them.

My question is a 50w Finnex is $39 on Amazon but a 200w is only $4 more or $10 more for the 300w that I currently use. I'd rather buy the bigger one for the small price difference as long as it isn't going to be too big for my small QT. Will that be ok?

 

[jccaclimber]

I don't like to have a heater so big that it can cook my tank if it gets stuck on. For this very reason if I need 400 W I'll put in two 200 W heaters. Also, the higher wattage ones tend to be much longer and may not fit the way you want in your smaller tank.

Beyond that, it will work. I've run a 300 W heater in a well insulated 20 gallon just because it's what I had spare at the time.

 

[minus9]

The margin of error in that small of a tank is very small, very small. It doesn't pay to go much higher in wattage. It would only take minutes for a large heater to cook your tank. Besides, is $4 worth the risk of cooking all of your inhabitants?
Just my two pennies.

 

[tkeracer619]

No, it's not ok.

 

[mattgumaer]

It can cook your tank quick. It also will likely cycle on and off much more frequently, leading to the potential for earlier failure. Without and independent controller, I definitely wouldn't risk it. If you have to buy a heater (rather than using a spare you have kicking around), I would definitely buy the correct size for the tank.

Matt

 

[smatter]

You turn your tank into a Sous-vide!