A quick and dirty fish tank heater for cold nights

[davidstcldfl]

Actually, it was a 110 volt element. I wonder if a 220 element could be used with only 110 volts?

Yes sir, it'll work...but it'll use about 1/2 the rated voltage.
When I bought my house, my hot water tank only had 110V going to it. It heats fatster, since I ran 220 to it.