Aquariums, Information

How Long Does Carbon Last in Aquarium Filter?

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by Jason Matthews


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Many aquarists use activated carbon in their aquaria. In fact, it is one of the most popular filtration media on the market. However, there is a difference in opinions when it comes to using carbon in a fish tank. Some aquarists believe it should be the media of choice in filters while others feel that activated carbon should be used just when you need it the most.

Whether you use it occasionally or as a standard media, you will want to know how long does carbon last in the aquarium filter. However, before that, you should know why aquarists use activated carbon in their fish tanks.

The Reason to Use Activated Carbon

Water contains a lot of contaminants, like chlorine, phenols, and chloramines, that are harmful to the inhabitants of the fish tank and also alter the quality of the water. By using activated carbon, you can rest assured that it will absorb these contaminants and prevent the water from turning yellow.

It is also prudent to note that activated carbon does not remove toxins like ammonia, nitrates, and nitrites. Hence, when you first set up the fish tank, using activated carbon to get rid of these toxins will be futile. You should take time to learn about how to address spikes in the levels of ammonia, nitrites, and nitrates so that you use the right method. Also, activated carbon will not get rid of toxic heavy metals. You will need to treat the water with the right product to address concerns related to the presence of heavy metals in the water.

How Often to Change Carbon in the Aquarium

Many people have the misconception that carbon will last for several months while others believe that it lasts just for a few days. How long the carbon lasts in the aquarium filter depends on numerous factors.

Related article: How often to change aquarium filter

Each brand uses a different temperature to heat the carbon to activate it. Depending on the temperature used to charge the carbon, your activated carbon can last for two, three, four weeks.

Also, the cleanliness of the water affects how long the carbon lasts. If the water is dirty, the activated carbon will not last too long. If you have a reef fish tank, the corals will release biochemicals and the carbon will absorb them. Hence, the carbon will not last as long as it would have if you didn’t have corals.

The pores in activated carbon increase the surface area of the carbon. However, as it absorbs contaminants, these pores gradually get blocked. Once all the pores are blocked, the carbon will be unable to absorb any contaminant present in the water. When that happens, the carbon is no longer charged and it is advisable to change it.

Related article: How to change aquarium filter without losing good bacteria

The Bottom Line

If you use carbon as a filtration media in your aquarium filter, you should change it every two to four weeks based on the presence of the bio load in the aquarium. Remember, if there is a high bioload, the carbon will lose its charge within no time. That is why you should place it in the filter after placing the mechanical filtration media. That will ensure that the carbon will last a little longer.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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