How to Tell If The Aquarium Heater Is Broken

Lauren Kiekbusch
How to Tell If The Aquarium Heater Is Broken

Aquarium Heaters are one of the most essential tools for aquarium owners. It is more essential now as it is the winter season. Even except that, a fish tank heater is essential for the breeding process, only if you are willing to.

You can almost replicate the water temperature, as per the species of fish you have in your tank. The water heater comes in many shapes and sizes.

During the warm season, you may not have needed it. You might have stored it away. But during this winter season, if you want to use it again, you must check for any faults with the heater. To be specific you should check in, is it broken or not.

Look for signs such as if the light is on, hot water, etc. You will light up the water flow around the furnace with a torch. If the heater works, something next to it will blast like a torch, so that you can see the flow of water under the light.

Let’s discuss furthermore, and we will elaborate more in the following segments. 

Also worth reading;

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  2. Is The Common Super Glue Aquarium Safe?
  3. How Much Gravel Does An Aquarium Need?

Aquarium Water Heater Working Process

You need to know how it operates to decide the problem. A heater for aquatic fish is used to heat water in aquariums in the hobby of fish maintenance.

Temperatures from 22 to 30 °C (71-86 °F) are held in most tropical freshwater and marine aquariums. Glass immersion and gravel heating forms are included. It can be put under the aquarium, too, like Heating pads. 

A heater in an aquarium turns electricity into heating. When water absorbs heat fast, the water surrounding it is heated by a heater. But it has to be in the water with sufficient ventilation, to get a heater going.

Just when they exceed the temperature of the environment, all aquarium heaters turn off. There’s no reason to think about overheating the water. The heater is turned on automatically if the water becomes warmer than the fixed temperature.

How To Check If The Aquarium Heater Is Broken

Often a heating device will get harmed as it gets too hot or too cold like any electrical appliance in your building. Continue to read To identify the most typical fish tank heater problematic spots.

1. The Famous Bucket Test

Let’s start with something smaller and compact. If you have a 10 or 20 Gallon Fish Tank, then you have to wait one day for the water to heat up. The smaller the amount faster the water will heat up. Take a bucket that may contain 5 to 7 liters of water. Do not forget to measure the temperature.

Aquarium water heaters are not like typical water heaters that may heat the water within 10 to 15 minutes or around that. It takes a lot of time. When it is about a small bucket with 5 to 7 liters of water, it will take at least 3 to 4 hours. 

In this case, you do not need a thermometer. If the water feels warmer than before, then it is working just fine. If the water is not even warmer as it should be even after a long time. You should take it to repair or change it permanently. 

2. Hand Test

This may seem like dangerous work, and it is indeed. But you can do it easily and unharmed if you follow as said.

Your Fish tank water heater will take a lot of time to heat the tank water. What you can do is, after putting the heater in the water, take your hand towards the heater slowly. As you approach close to the heater, you should feel hotter.

If, even after you are too close and able to touch the heater then no doubt it is broken. Or else, your hand should have burnt (just kidding). If the water around the heater feels warmer, then the heater is just fine. 

How to Tell If the Aquarium Heater Is Broken

3. The Light Test

While looking towards a long road on an extremely hot day, you may see blurry vision due to the heat. The same event may happen with a water heater in the fish tank. Put the fish tank heater in the water and wait for a while.

Within that time, the water may heat up a bit. Now take a flashlight and put it on the edge of the heater. You may see blurry vision due to the heat of the heater. If there is no blur vision, that means the heater is not working. 

4. Thermometer Test

Now, before you do this test, you must know, thermometers do not always show the correct result, either it is a digital thermometer or an analog thermometer

Now, you can use your regular tank or even smaller ones. The result will be the same for any shape and size. The only thing that may vary is time. Less water will take less time to heat up. 

You must determine the water temperature. To get an obvious result, set the water heater temperature higher than your room temperature by a few scales. After the required time to heat up, measure the water heater, and subtract it from the previous one. 

Remember, you should not use water that is colder than your room temperature. Try to keep the water temperature at or close to the room temperature for perfect measurement. 

5. Check Tank Temperature

From the above-mentioned ways to determine if your tank water heater is broken or not, you may have an idea of the time you need to heat the water. Now, after turning on your water heater in the fish tank, leave it for a day or two.

We know this is a long process. But the result is what we seek. The water should be heated up by then. Now just simply touch the tank. If it feels warmer, then the tank heater is not broken. 

6. Check for Heater Light

Most commonly, the water heater light won’t go on if it is broken when you turn it on. Many heaters have metal bodies that may be covering the light from being seen. In that case, just follow the process above.

7. Check for water Drainage or Leak

Most of the time, the problem may not be with your water heating device. If your fish tank uses a water-flowing device and has a drainage system in the bottom, please check if the drainage system is okay or not.

Sometimes the water may flow through the drain and could not even get the chance to heat up. In certain situations, fish tank heating systems are intended to be leak-proof, but water can leak into the lower drainage troughs over time and this results in low output.

8. Excessive Heat

All the above options were about the fish tank water not heating up. But you can also tell it is broken or defective if it overheats. When it appears to smoke or makes extraordinary sounds, the aquarium heater is typically brokered.

Besides, the fish can be fried in water when the temperature of the tank is 120 degrees. The valve at the base of the tank can be checked and shown if it is obstructive or leaked.  When   You smell black smoke, it may feel like ammonia.

Reasons Behind a Broken Fish Tank Water Heater

These are the reasons behind a broken fish tank water heater;

1. Untidy Aquarium 

If you do not have the right purification device on your tank, you will also damage your heating unit. Fish, plants, and designs evaporate from oceans. When your filter doesn’t have a water reserve, it will dry up, so it has to be changed periodically. 

You will also need a heating unit upgrade. Tank washing devices are designed to ensure that the water remains clean. It could be time to change your filter if you have just been using tap water.

2. Improperly Plugged In

Another reason your heating system could fail is that it has been incorrectly attached. Like standard household devices, some heaters have been designed to operate without electrical outlet control.

Unfortunately, certain fish tank heating systems are designed specifically to operate on a power supply in a fish tank, so you can ensure your heating system is not one of them.

3. The Heater Defects 

We are talking about manufacturing defects here. It happens often. You buy something from Amazon or a local store, you find it not working or not working properly or broken. The easiest solution for this, buy a good heater to preserve the good condition of your fish and a spare one to decrease damage.

4. Badly Heatproof

It often happens with most heating devices. The fish Tank water heater is not any different from that. It may be made of glass or other metal. If it exceeds the heating level, it could malfunction. Keeping the increasing heat in check is also a responsibility. 

5. Excessive Use

If you have used a room heater, you may understand this better. A room heater doesn’t matter how good it is, if used excessively, it starts showing malfunctioning. Almost all the devices that produce heat, are likely to have this kind of problem. After using it for a while, give it some rest. 

Don’ts With Aquarium Heater

There are some easy things to do to keep you from recovering from an aquarium tragedy.

  • Say no to the broken heater: Don’t try a faulty heater or patch it. You can be reasonable, but a lot is involved. Throw it out and buy another. Finally, it costs you a heater of consistency well below one or more of the fish in your pool.
  • Don’t keep dirty:  Regularly clean the heater and other items, especially to keep the heater free from salt and to leave the case, caked in salt, for a few days. The white aggregation of water minerals is a salt creep.

    There is also maybe calcium and other minerals, but not just table salt. When the salt creep emerges, a lot of effort should be done to eradicate them and new water will not be just swept away.
  • Don’t keep it connected while water changes:   Remove the heater as the aquarium temperature switches or it is separated from the water. Just to avoid surge heating that could cause harm. Hold the water level in the tank so that every special form of the heater is fully submerged.
  • Don’t Buy Cheap Ones:  You may have reasons behind buying cheap fish tank heaters. But as mentioned above, your water heater won’t cost you more than buying all the fish again. And the mental shock, you won’t be overcoming from that any time sooner.
  • Don’t neglect temperature rising:  If you are already using a thermometer, then keep the temperature in check. If you see the rising temperature, do not neglect it. If you are not using a thermometer, and if you notice any unnatural movement among the fish, do not delay checking the temperature. You probably do not want to see almost boiled, dead fish on the surface of your fish tank.
  • Do not be “ I can do it myself”:  We know, you may have all the mechanical knowledge. But still, do not neglect the instruction that comes with the product. It is given for a reason. Any faulty connection, you may repay with lives, either of your fish or your own. Be careful!!

Frequently Asked Questions

Can the Aquarium Heater be turned on all the time?

The heater can be left on 24/7. Aquarium heaters have an internal heat-extinguishing thermostat when the temperature exceeds a certain amount, maintaining the water temperature within several degrees of the desired atmosphere.

Why does the heater keep turning off?

Heaters for aquariums tend to be on and off. Increase the thermostat setting if the heaters keep away and the temperature is too low in the water. It wants to begin spinning, but the temperature must be controlled so that it cycles properly until equality is achieved.

Should you worry about Bill?

A 30-gallon tank that is heated to 72 F (22 C) is eaten approx. For example, A year of 110 kWh. It absorbs around 440 kWh per year in the same tank heated at 82 F (28 C). That’s four times more! We don’t think you can if you aren’t using it excessively.

What is the perfect place for placing the heater?

The safest spot to place a heater in your home aquarium is next to the full flow of water, such as the outlet (or the inlet) from the filter and the power source. With water going straight through the radiator, hot water flows around the tank easily and simultaneously.

What should be the ideal temperature?

You find a temperature dial knob on the end, which helps you to adjust the desired temperature if you use a submersible aquarium heater. Aquarium heaters for tropical fish are typically set and calibrated, and the temperature range available is between 68F and 88F.


    The most critical item in your tank is potentially your heating unit. If you notice that the patch or replacement is broken, it is a simple procedure and does not last more than an hour.

    Your tropical fish is kept alive and content by a water heater. Never miss it when the fish are tropical. In the same tank, don’t combine tropical and non-tropical fish. Buy a decent heater for several years so it doesn’t fail easily. Electricity leaks are still likely, as with all electrical devices.

    And if the radiator is completely waterproof. You don’t know if it’s going to shock you and spill. Better safe than guilty, unplug your hands into the water before you bring them.

    One final tip, change your fish tank heater if it has become too old.

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