Eheim Jager TruTemp Aquarium Heater Product Demo

We’ll be discussing the Eheim Jager TruTemp aquarium heater in today’s video installment.

Eheim Jager TruTemp heaters are a best-seller because they are affordable, reliable and they allow you to calibrate the thermostat.

The calibration feature is unique because it allows you to compensate for any differences between the heater itself and your aquarium thermometer. With TruTemp heaters, you get truly precise temperature control which is essential when caring for delicate aquatic life that is sensitive to water conditions.

The heater will be factory calibrated right out of the box. Adjust the blue thermostat dial to your desired aquarium temperature and place the heater inside your aquarium water. Wait 30 minutes before plugging the heater into a power outlet to give the glass time to adjust to your current aquarium water temperature.

Let 24 hours pass. Then check your aquarium thermometer to see whether or not the heater has achieved your desired water temperature. If not it hasn’t, you can adjust the red dial to the observed water temperature in your tank. Then reset the blue thermostat dial to the desired temperature. You will have then calibrated the heater to make up for any differences between your aquarium thermometer and the thermostat on the heater.

If you have any questions about the Eheim Jager TruTemp Fully Submersible UL Approved Aquarium Heater, please leave us a comment here on YouTube or call us at 1-800-566-FISH (3474).

If you’d like to select the right size heater for your aquarium and/or read 140+ product reviews by hobbyists just like you, please visit our website:



Amrita Thakur says:

Can pleas tell me how to reset it on factory settings
Because of not calibrated perfectly


Had one, it’s a piece of SHIT

Jürgen Kaßnitz says:

You have only shown how to recalibrate the heater if the actual temperature is lower as desired. But how do I have to recalibrate if the actual temperature is higher? How can I twist the red arrow in this case?

david roberts says:

I have instructions from the company tech department because this piece of crap i have didn’t work as you describe…..they wanted me to recalibrate it to factory setting – by turning the blue and red dial to 79 degrees – and plug it in for 24 hours to see if it would maintain a temp of 78-80 degrees for 24 hours – which it did not.  Then if it did – to turn the blue dial to 85 degrees for 10 seconds and then back down to the desired temperature.  (no where do you find that last part in the instruction sheet !!!) – anyway this is a piece of shit heater so I’m giving up and going with something else that will work.   

Ferrari FX says:

Not gonna lie I bought this thinking it was a higher end heater. Its junk. Almost any other option is better.

Panagiotis Sarris says:

What is the difference between jager and thermo models? They look the same but some are labeled as jager and some as thermo

Maria Henderson says:

what if the adjustment is more than 4 degrees?

Danny Bolton says:

The first time I used this, my temperature spiked up to 86° F. The product instructions are ATROCIOUS in the box. It says nothing about allowing your heater to sit in the tank for 30 minutes to adjust to the temperature. It simply says to move the blue dial to the desired temperature.
The red indicator arrow is not explained at all.

This heater is only good for individuals who are willing to spend an extra 2+ hours doing research on how to work it properly. Even then, the calibration mechanism is just too much. If you notice a 2° F discrepancy from your heater to your thermometer, it takes a second of math to figure out the difference.

John Munoz says:

if my tank watter is 68 and the blue diel is in the back how the hell do you get the red arrow to the back if it whont let you turn it all the way

frank1971ification says:

please reply back. I got 4 Jäger TruTemp 300 Watt Heaters rated at 159-264 gallons for each one. my question is would 4 of these be able to keep my turtle tank over the winter in my garage at a warm temperature. P.S I live in Canada and my tank has 80 gallons of water in it.

TechDJ87 says:

I’ve Had several of these and they have all gone kaput after a year or so.
You adjust the red dial to suit, well that’s all well and good but I’ve had mine over as far as it will go and its still a further 2 degrees warmer. That’s Way out of the manufactures specification as they are meant to be accurate within the red dial calibration. Along with some of the issues I’ve had with there external filtration products I’m beginning to question the overall quality of Ehiem themselves.

Lane Widick says:

I have one of these, and I can’t seem to get the “on” light/indicator light to come on at all. It is not heating anything. I have it set to 80, but i’ve never seen a light come on. My aquarium thermometer says it is 75-76degrees – so it should be on, right? Thanks in advance.

TheMrProGamer2012 says:

You guys should should give one out for free

KRT Mobile Valeting says:

is this heater totally submersible? so i could mount it horizontally ???

Nurul Hassan says:

I want to know about (sobo aquarium heater’s)

 Write a comment


Do you like our videos?
Do you want to see more like that?

Please click below to support us on Facebook!