Do I Need Carbon In My Aquarium Filter – Solving The Myth

Last Updated on January 20, 2022 by admins

Do I need carbon in my aquarium filter is one of the most common questions asked by fans of the aquatic world. Click to learn more.

Carbon, lat. Carbo is a chemical element with a simple symbol C and atomic number 6. It can be found all around us, most interesting of all and it forms more compounds than all the other chemical elements combined.

Activated carbon has been used for decades as part of our aquarium filtration systems. However, many spears are still breaking around it. Some believe that it has no purpose and that its use should be stopped as soon as possible. On the other hand, the vast majority consider it very necessary, moreover – it is considered as the standard.

Therefore, today we will answer one of the most burning questions – do I need carbon in my aquarium filter.

Learn more about Wet/Dry Filter For Freshwater Aquarium

What Is Activated Carbon?

Activated Carbon is a very porous substance that has been heat-treated at extremely high temperatures.  This heating process has created tiny pores and a huge surface that attracts and retains organic chemicals inside it.

When it comes to creating activated carbon, several different methods result in different forms of the material. This diversity makes it practical and convenient for all users.

What Is Activated Carbon

Learn more about: How To Make Activated Carbon For An Aquarium

The most famous forms are:

  • BAC – bead activated carbon,
  • EAC – extruded activated carbon,
  • GAC – granular activated carbon,
  • PAC – powdered (pelleted) activated carbon.

Activated charcoal for aquarium filters is most often made of materials such as bituminous coal, peat, lignite coal, coconut shell, and wood.

What Does Activated Carbon Do?

This is a great way to remove unwanted chemicals, contaminants, or even medications. It breaks down water-coloring substances (chloramine and chlorine, tannins), and also water-smelling substances (phenols). So, it does both, cleans the “stinky” aquarium, and makes the water cleaner.

Keep in mind that Activated Carbon is not omnipotent. There are, however, some toxins, poisons, and threats that it will never be able to remove. – So it’s about ammonia, nitrites, or nitrates, as well as heavy metals, such as lead or copper. You will need to use other available forms and methods to solve these problems and preserve the health of your aquarium environment.

Does Activated Carbon Absorb Or Adsorb?

Activated Carbon for aquarium filters has adsorption power. Although there are stories that once it reaches its capacity, it starts releasing adsorbed materials back into the water – this is not true. Although technically possible, it requires special conditions that the aquarium never achieves.

How Long Does Carbon Last In Aquarium Filter

The frequency of carbon change in your aquarium depends on several factors. This primarily refers to the number of fishes, the size of the tank, and the quality of the carbon you use. You can choose a time frame of 6 to 8 weeks.

How do you know it is time to change the carbon filter? You will most easily recognize this by these factors.

Carbon Filter Quality

Invest in high-quality, well-made ones. They will definitely last longer. Low-quality carbon (or substitutes for it) can last from one to four weeks, while high-quality carbon can last up to three months.

Contaminant Quantity

When eventually filled with the compounds it removes, charcoal, unfortunately, stops working. This happens because the carbon’s surface becomes full of all the impurities that it has adsorbed and the purification process stops. So, the more contaminated it is, the more frequently the filters need to be changed.

Manufacturer’s Recommendation

Finally, we must not forget the manufacturer’s recommendation. On the packaging, you will find all the information on how to take care of your activated carbon filter and how often to change it. As long as you follow the instructions properly, you don’t have to worry about the health of your aquarium.

Recharging – True Or False

Just like the stories our grandparents once told us a long time ago, we fear that the stories of recharging activated carbon are just a mere myth. The reason is very simple. Conditions are extremely difficult to achieve at home. The temperature and pressure required to recharge your old and used activated carbon can’t be achieved in your kitchen oven.

There are much simpler and easier options. Simply buy new carbon at a fish shop and keep your aquarium healthy for longer.

Where To Place Activated Carbon In Filter

It is generally known that it loses its effectiveness with high exposure to contaminants/debris. Therefore, it would be best to place your activated carbon after the mechanical filtration medium in the filter. This will allow it to work properly and extend its life.

How Much Carbon Should I Use?

Its quantity depends on the tank itself. If you are a beginner, it would be best to start with a smaller amount and monitor the clarity and smell of the water to determine if that amount is ideal. Remember – the less carbon, the more frequent the change.

So, Do I Really Need Carbon In My Aquarium Filter?

As we said at the beginning, opinions are divided. Its use is optional and by no means necessary. Regular water changes and checkups will suffice to keep water chemistry at the required level.

These are the Pros and Cons of using activated charcoal for aquarium filters.


  • Removes various dissolved organic matter and toxins
  • Supports the bio-filtration process, and makes it more efficient


  • It has a limited (short) lifespan
  • Can remove some trace elements. (It is necessary to pay attention to the planted aquariums and add additives if necessary.)
  • Activated carbon leaches phosphates

Click here to learn more about Activated carbon (also called activated charcoal, or activated coal).

To Wrap Things Up

Using charcoal in an aquarium has very great benefits. It helps to clear out harmful elements from the water making your aquatic world a safe place to live. Make sure you choose the one that is ideal for your aquarium and change it regularly.

The answer to the question “do I need carbon in my aquarium filter” is still optional and depends on your preferences. However, if you are in the mood for extra care and maintenance, you can certainly use it. What is your opinion on its regular use? Write to us below.

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