How Long Does Carbon Last In Aquarium Filter?

-- By Carol

Having an aquarium comes with its own set of responsibilities.

One of the most important factors that contribute to the success of an aquarium is its filtration.

The majority of filters include the use of charcoal or activated carbon (AC) for a number of reasons.

Activated carbon has been utilized by aquarists to clean their home aquariums.

Ever since more innovative filters have been introduced, a lot of people are debating whether AC should be used or not.

Many believe it should be used, while others feel like it should only be used for special needs or should not be used at all.

Despite the constant debate, AC still remains the greatest selling filtration product for aquariums.

These carbon filters only function as long as the charcoal is capable of absorbing impurities from the water.

Here’s a complete guide to what activated carbon can do for your aquarium and how long it lasts in your aquarium filter.

Table of Contents

What is Activated Carbon?

Charcoal, lignite, or wood that has been treated at extremely high temperatures, gets charged and turns into activated carbon.

By activating the carbon, a lot of tiny pores are created in the process, allowing the surface area to expand.

This activated carbon, often abbreviated as AC, starts acting like a sponge.

AC is used in the filtration process of aquariums as it is useful in drowning out foul odors and trace elements from the aquarium water.

By acting as a sponge, it easily absorbs these unwanted elements and aids in the cleansing of your fish tank.

Different types of activated carbons are made using different methods. As an aquarist, it’s your job to make sure that your aquarium remains clean so that your fish can thrive in it.

While some aquarists use carbon daily, some don’t prefer to use it at all.

Activated carbon is available in different shapes— the most popularly used shapes are granules and pellets.

AC is also available in powder form, but that isn’t preferred to be used in aquariums.

Remember that activated carbon that is light and has high porosity will have a greater surface area.

A greater surface area implies that it can absorb more impurities; hence, it will filter the aquarium water more effectively.

Tap water filters are also designed to utilize activated carbon as they help get rid of odor, so this can be used to benefit your aquarium too.

What is Activated Carbon Used for in Aquariums?

Now that you know what activated carbon is, it’s time to learn about what it does.

carbon is used to get rid of any odor, yellow compounds, medications, fertilizers, and supplements that are found in the aquarium water.

If you don’t change the water in your aquarium for a few days, you might notice a smell.

Adding some activated carbon to the aquarium will make the smell disappear instantly.

You probably want to make the best use of your aquarium’s lighting because let’s face it, the lighting makes the tank look more beautiful.

However, the yellowing compounds in the water can hinder this aesthetic experience.

You can add activated carbon to the filter to increase the light penetration in your fish tank. Remember to use carbon cautiously as it might lead to a light shock for corals in your aquarium.

This relies upon how yellow the water in your aquarium is, to begin with.

You can try looking into your aquarium; if you can’t see the other side clearly, then your aquarium definitely needs some cleaning.

Activated carbon makes a massive difference in the clarity of the water. It will clear up any yellowing compounds or dissolved organics from your aquarium water right away.

If you’ve purchased any fish recently or you have a new aquarium, you might want to quarantine the aquarium by medicating it.

You may need to add some activated carbon to get rid of any medication from the water once the treatment period is over.

Remember to filter out the medicines once your fish is done with the treatments.

Also, you will have to remove the activated carbon from the aquarium filter before starting the medicinal treatments; if you don’t do that, the medicine will not have any impact.

The key is to keep the activated carbons offline when using any supplements for the fish.

Once you feel like the supplement served its purpose or enough time has passed, then you can start using the AC in the filtration system again.

Activated carbon is a great way to extract organic chemicals from aquarium water.

Organic chemicals are not to be mixed up with three usual chemicals that are ammonia, nitrate, and nitrite.

These chemicals are inorganic and carbon will do no good to them.

So, if you’re adding carbon to remove a substance such as ammonia, you’re barking up the wrong tree.

How Long Does Activated Carbon Last?

This is the most popularly discussed topic when it comes to using activated carbon for the aquarium filtration process.

While some people think activated carbon lasts for only a few days, others believe that it serves its purpose for months.

In reality, this solely relies on the application of carbon and how dirty the aquarium is. The dirtier the water, the sooner you will have to replace the carbon.

Many people choose to keep their aquarium clean at all times, allowing the activated carbon to serve its purpose for a longer time. Let’s take an example to understand this.

If you have a tank full of corals, they will constantly release biochemicals that will affect the water in the aquarium negatively.

The same applies to macroalgae; they will also release biochemicals that harm the corals.

However, running the filter along with activated carbon will seriously help lessen this impact as the AC will absorb these chemicals.

Although activated carbon is one of the most absorbent filters, the more it absorbs these biochemicals or other dirt, the quicker its tiny pores will get jammed.

Eventually, almost all the pores of the carbon will get clogged and its ability to absorb dirt or biochemicals will reduce.

How Long Does Activated Carbon Last in Aquarium Filters?

Activated carbon in aquarium filters should be changed every 2 to 4 weeks. However, if the water of the aquarium is extremely dirty, you might have to change it every week.

In addition to this, the bioload of your fish tank plays an important role in determining the life of the activated carbon in your aquarium filter.

What is a Good Activated Carbon for your Aquarium?

You need to consider a few factors when deciding what kind of carbon you should use in your aquarium.

Firstly, you need to consider the particle size of the card.

If you choose to use tiny particles that are less than 2mm in size, you need to use them with a media bag; otherwise, the particles will spread through your aquarium.

It is recommended that you purchase carbon that is washed in hydrochloric acid as it contains the least amount of phosphate and doesn’t have much of an impact on the aquarium pH levels.

Pellets and granules are both great options.

While pellets are good for allowing a better flow through the reactors, granules tend to have a larger surface area that makes them last longer.

While comparing various activated carbon brands, you might also want to compare their weight for a given volume.

The lighter the activated carbon is, the better it will be. Lighter active carbon is also more porous. You should definitely consider researching the best AC brands before buying AC because you want the best for your aquarium.

How to Change Activated Carbon in Your Aquarium?

The activated carbon needs to be stored in a mesh filter bag in order to be used.

For every ten gallons of water in your aquarium, only half a cup of activated carbon should be used.

You might find some extra carbon dust when taking out the carbon from its respective container.

You should run the activated carbon under running water for a while, just to be on the safe side.

Make sure to get rid of the old carbon lodged in the filter system of your aquarium. It’s also essential that you place carbon in the right place and at the right time in the filter.

If AC is placed too early, then there is a high risk of it becoming biologically active – this means it will get smothered by nitrifying bacteria.

This will make the activated carbon lose its surface area and it becomes completely redundant.

The Bottom Line

Carbon filters aren’t necessarily important to maintain a healthy aquarium.

Frequent water changes and regular filtration are more than enough to keep the chemistry of aquarium water under check, but activated carbon can be very helpful as well.

It is crucial to remember that carbon gets exhausted rather quickly if it’s being used in an aquarium filter.

Hence, a decision needs to be made between using activated carbon on an ongoing basis or replacing it daily.

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