What size heater should I use for 10 gallon tank

Question
I had a 50W heater for my 10 gallon tank and the temperature would only get up to 68 degrees on the highest setting.  I upgraded my heater to 10" 100W. I have the setting all the way up to high and the temperature will only go up to 72 degrees. What is going on here? Thanks so much

p.s. I have 1 betta fish in the tank

Answer
Hi Kristen;

What is the temperature in the room? If it tends to be pretty low maybe the heaters can't get it high enough?

Is there power to the heater all the time? Some room light switches operate one or more wall outlets too.

Try another thermometer, maybe it isn't working right?

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Chris Robbins

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