55W Heater Not Accurate

[alien-planet]

So today i decided to buy a 55w heater for my 2nd betta tank i had plans on using one heater to heat up both tanks once but from feedback i decided to instead get a 55w heater for the tank so anyways i set it at 28 degrees Celsius ( 82 degrees F ) but its not even reaching that i have a thermostat and its showing on 70 degrees F so what's the problem ?

its not even a large tank ! I think it could because i need a 100watt heater any ideas ?

 

[eduller]

How large is the tank and what is the ambient temperature of the room? A 55W heater should be fine for most tanks 50-75 L and below unless your house is super cold. What kind of heater is it? Sometimes they need to be calibrated. What happens if you set the heater at a higher temperature?

 

[alien-planet]

Click this link to see the size of the tank , bare in mind the heater you see in that video is not the one i am having issue with its called : Aqua One 55w glass heater that's having issue with. If i adjust the heater higher it goes to the temputure i want it but its at 32 degrees Celsius to get at 80 degrees Fahrenheit. I am worried it will fry the betta female one day because tempture its at.

http/m.youtube.com/watch?v=opqcmAI9htQ

the tank u see in that video and its heater is working fantastic i suspect its because its a bigger heater.

 

[eduller]

It's pretty common for a heater to not keep the exact temperature you set it for. Mine are usually a few degrees off in either direction except for my one inline heater. I think it will be fine. There's no more chance of it going rogue and overheating than any other heater just because the calibration is a little off.

 

[DrRob]

Very few of them are actually that accurate on their setting. There are some odd ones like the Jagers that can be home calibrated but generally it's a bit of set it and tweak.
 
The one thing to test is that it actually does go off if you turn the temperature down, occasionally they'll stick on, which isn't good.