Aquarium Heater Wont Turn Off? [Explained]

Aquarium Heater Wont Turn Off? [Explained]

There’s a possibility that the heater for your aquarium is not operating as it normally would.

You could be questioning why your aquarium heater won’t turn off in that regard.

Your aquarium heater might not turn off due to having a larger aquarium. As the heater might not be able to heat all the water thoroughly. A broken heater is another potential for this. This causes the lights on the heater to not work. There is a reasonable chance that your heater is inoperable.

If you are further curious to know about this topic, then we’ve got you covered. We will also assist you in identifying the ideal resolution to your specific situation.

So, to know more, keep on reading!

Aquarium Heater Wont Turn Off? [Explained]

Why Won’t My Aquarium Heater Turn Off?

An aquarium heater is an essential device that is utilized in the hobby of fishkeeping.

Aquarium heaters work very efficiently when it comes to keeping fish healthy and sound.

It has the potential to raise the temperature of the water that is found inside aquariums. Most manufacturers indicate the change in the water temperature by using different lights.  

We will help you troubleshoot issues with the aquarium heaters light on but not working. Because it can lead to issues such as an increase in temperature. 

You may find that your aquarium heater has stopped working. This is bad when it comes to maintaining a healthy population of fish in your aquarium. 

You’re probably curious about the cause of the problem. We will now go over the plausible causes alongside you.

Reason 1: Insufficient Aquarium Size

Wrong-size aquariums can be the reason why your aquarium heater is not shutting off automatically.

Having too large an aquarium can cause the water heating to malfunction. This procedure may continue for a considerable amount of additional time. This can make your aquarium heater not shut off.
If you follow the procedures below, you should be able to resolve this issue.

Solution 1: Find an Aquarium That Is Suitable for Your Heater

You need to have an appropriate heater for your aquarium. Try to get your hands on the proper size aquarium that goes with your heater.

This would ensure that the water inside the aquarium is getting heated evenly. This would also let the automatic heating system work effectively.

If the heater is designed for a larger volume of water, then it should be fine. But if you have a smaller heater, then it might not work. 

Using a larger heater in a smaller tank will not have any adverse effects. However, keeping a tank that is larger than necessary can also become problematic.

Accordingly, you need to assure that you own the appropriate heater.

Solution 2: Manually Turn Off the Aquarium Heater

You might not need to keep the aquarium running all the time.

Turning off the heater can make the water stay between 74 and 77 degrees. If your aquarium water remains the same temperature, then you aren’t required to keep it on. 

But just in case the water temperature gets cooler, you might just require it at night.

You must unplug it for the time being. However, you must never forget to keep a close watch on the degree of the water. It’s important to know how to get rid of aquarium water in case something goes wrong.

Reason 2: Aquarium Heater That Isn’t Operating Automatically

There is a chance that the heater in your aquarium is not operating efficiently. There are a variety of feasible explanations for this behaviour. 

Due to some form of an operational issue, the aquarium heater can act differently. Sometimes, the green or red lights do not work according to the functions of the heater.

You may even find your Aqueon heaters light turning off. These issues can happen due to the aquarium heater not responding as it typically would.


If these issues occur, then you might want to know how to reset the aquarium heater.

You can solve these issues by following the steps mentioned in the next few sections. 

Solution 1: Reset the Temperature Settings 

To change the temperature on your own, your aquarium heater must have the settings on it. 

If you notice a red circle on the top of your heater, then this might work. You can adjust the parameters from there to stop your aquarium heater overheating problems.

In that scenario, you will need to turn off the heater by unplugging it. After doing so, rotate the red ring until it points to the right temperature.

Now, all that remains for you to do is make some adjustments to the blue top. It is also essential that you bring it to the proper temperature that you desire.

After you are done changing these settings on your heater, you should reconnect it. This should fix the issue of your aquarium heater not turning off.

Solution 2: Replace the Aquarium Heater

Sometimes your aquarium heater might reach the point of not getting fixed. If that occurs, then you will be forced to change it out with a new version.

You might wonder how to tell if the aquarium heater is working or not. 
You can find this out by moving your hand cautiously in the direction of the heater. If the heater emits heat and the water gets hotter, then it is functioning well. If you can not feel the heater radiating heat, then it is not functioning properly. 

If there’s no discernible shift in temperature, only then are you permitted to operate the heater. There is a high probability that this indicates that the heater is broken.

We hope now you can get your aquarium working back to its normal state. 

Once your water is at the right temperature, you can add the fish.

You might want to have a look at these incredible heaters we have picked. The fish in your aquarium will remain in healthy condition with the help of these heaters.


Are Aquarium Heaters Supposed to Always Stay On?

No, aquarium heaters won’t always stay on. Most aquarium heaters are automatic. This makes it possible to detect the temperature of the water inside. Most aquarium heaters are set to turn off at a certain temperature. This happens when the water inside the aquarium has reached the right temperature. 

Can My Fish Get Damaged by the Aquarium Heater?

Yes, your fish can get damaged by the overheated aquarium heater. Although this is highly unlikely, the possibility still remains. If your fish gets trapped within the aquarium heaters, it can cause your fish some damage. There can be severe damage due to the fish getting overheated by the heater.

Could the Green Light on My Aquarium Heater Imply Anything?

Yes, the green light on your aquarium does indicate something. The green light usually represents the fact that the heater is functioning at the moment. Most heaters have a green light indicating that the heater is working on standby. The red light usually means that the water has started heating.

Wrapping Things Up

We hope our piece helps you understand why your aquarium heater won’t turn off

We also hope our suggestions can efficiently resolve these concerns. 

Having a backup heater is a knowledgeable recommendation that you should always adhere to. This would ensure that your fish are safe in case the first heater fails abruptly.

Thank you for reading!