Tank heater help asap

[teeneythebetta]

I have a 10 gallon tank that I temporarily moved fish & snails out of. I bought the "Via Aqua quartz heater 100 watt"

I carefully read all instructions. I put the heater in the tank vertically and let it get used to tank temp for 15 minutes before plugging in. I got it ready and set it at 79 degrees. But then I thought about it for a minute and I figured I'd set it down a few degrees because I figured if it heated it a little cooler it'd be easier to heat it more rather than cool it down. So I turned the knob down to 75 and the "on" light shut off. And it will not turn on again.

HELP.

[Jupiter]

Isn't that normal though? It'll only turn on when it needs to actually heat the tank? Or do you mean it won't turn on even after you turn the dail up to a higher temperature?