Hello!

Will a 100 watt heater (labeled for 30 gallons) in a 10 gallon tank turn off when it reaches the temperature set on the dial, or will it overheat the water? It is a Visitherm Stealth heater. I don't want to cook my fish. Thanks!

I think you're okay. I have the same heater (not sure of the wattage...would have to take it out to check it, and the fish are sleeping right now) in my 45g. tank. It's either the same wattage as yours or higher, so no worries. But in a smaller tank like yours, be sure to keep it away from where the fish can actually touch it. They are drawn to the warmth, and can burn themselves.

Darn it! I didn't answer your question.

Yes, they have a thermostat dial that keeps it at the temp set, and it will not keep heating beyond wherever you have it set. Sorry bout that!

Thanks! I wanted to know for future reference if I need to use it in my 10 gal QT.