Aquarium

How important is activated carbon in your aquarium

When you start fish-keeping as a hobby, knowing everything about ‘essential’ and ‘not-so-essential’ products is important. You must have understood by now that aquarium filter is one of the essential aquarium accessories. It is supposed to make the water appropriate for the fish’s survival by keeping it clear, odorless and hygienically clean. Also, a filter removes the medications and toxins from the water column.

You must have seen that a lot of aquarium filters are equipped with a cartridge of activated carbon but do you know how it functions and what it does to the fish tank? Although there are different types of filter media for different types of aquariums, activated carbon is the most popular. When used in right dose and maintained properly it can benefit the aquarium immensely.

In this article we will discuss everything you need to know about activated carbon.

What is activated carbon?

Activated carbon is a purer form of charcoal. Often people misunderstood activated carbon as activated charcoal. When the wood is heated at high temperature, the charred remnants of wood make charcoal. Charcoal is further heated at extreme temperatures that remove every bit of toxins and impurities from the wood, making it safe for aquarium. Furthermore, extreme heating makes charcoal porous. It allows more pollutants to get captured. Therefore, a purified version of charcoal makes activated carbon.

Most of the times you may find activated charcoal when searched for activated carbon. However, when it comes to fish tank, activated carbon is all that we talk about as it acts as an effective chemical filtration system.

Let’s find out the different materials that are used to make activated carbon and the different forms available for sale.

Types of Activated Carbon

Different materials are used to make activated carbon that decides the important factors-

Number of pores
Size of pores

The most popular materials used to make activated carob include wood, coconut shells, bituminous coal, lignite coal, and anthracite coal. Out of all these, bituminous coal is the most popular as it makes highly porous activated carbon and offer wider surface area for trapping the pollutants. Also, it can be easily regenerated.

Common Types of Activated Carbon

Apart from different types of activated carbon, you may also find different forms of activated carbons in the market. Each form serves specific function and can be purchased accordingly. The different forms commonly available are the following-

Bead activated carbon (BAC)
Extruded activated carbon (EAC)
Granular activated carbon (GAC)
Powdered activated carbon (PAC)

Out of these forms, GAC is commonly used to serve filter usage as also the most common form of activated carbon.

Common disbeliefs regarding activated carbon filter

Activated carbon is used in many freshwater and saltwater aquariums as an efficient filtration system. However, there are a few skepticisms about its efficiency and the work it does for the aquarium health. Some common disbeliefs are:

Activated carbon removes essential nutrients from the aquarium water: Whether the activated carbon removes ammonia, nitrite and nitrate from the water column or not has always been one of the most heated discussions among the hobbyists. While some believe that adding filtration system with activated carbon traps the minerals and disturbs the water chemistry, some firmly believes that it does not create any trouble to the nutrients and can be added to new and struggling aquariums. At the same time, it is believed that activated carbon also removes trace nutrients and no matter how much fertilizers or boosters you add, they will probably get filtered out.

Our Opinion– Although it is unlikely that activated carbon will eliminate good amount of nutrients from the water column, it is not completely impossible. The best thing is activated carbon does not influence the alkalinity or hardness of water.

Activated carbon leaks back pollutants once full: Activated carbon leaking back the held impurities into the aquarium when the pores overfill is again a misconception. However, the aquarists need to make certain adjustments with the filtration system to avoid it completely as it could be possible to some extent.

It has been reported that a few filtration systems with activated carbon contain phosphate that may leak out over time. However, the amount was insignificant and do not pose any harm to the aquatic life.

Our Opinion– Always go for activated carbon from a reputed brand as they will perform best.

Benefits of activated carbon in fish tanks

Activated carbon is widely used in aquariums as it solves many purposes. For instance, it works on the impurities; make the water clean and clear by removing tannin content and also eradicates the awful odor that develops over time in the tank. Some common benefits you may reap by using activated carbon include the following:

Removes the odor from the aquarium– The absorption process of activated carbon helps to take out the awful smell from the tank. The porous surface of activated carbon traps the liquids and gases into a thin film that subsequently gets dissolved or incorporated into the carbon. The porosity of activated carbon absorbs the entire odor particles. However, you need to make sure that you change it after every 3-6 weeks for the best results.
Clears the water and makes it transparent– If you have been using driftwood or peat moss in your aquarium, you might notice the change in water color. It usually happens because driftwood and peat moss leaches tannins when kept in water for longer duration. Just like absorbing odor, activated carbon also absorbs tannins and removes cloudiness, brownish and yellowish color from the tank water.
Eradicates toxins from the water– Toxins may enter the system through different ways. If you are a reef enthusiast, the chances of increased toxins in the water is high. While some toxins are not highly dangerous to the aquatic life, some like zoanthis and palythoa release palytoxin that may be fatal. If you have activated carbon, most of the toxins get eliminated before they may create any nuisance in the tank. At the same time, if the impurities like smoke, aerosols or any other contaminants enter the tank, they too get eliminated with activated carbon.
Removes medications– Sometimes we may add certain medications in the aquarium to treat sick fish. Medications are also used in quarantine tanks. If in any case you want to get rid of medications from the tank, using activated carbon is the best choice.

How to use activated carbon in the aquarium

Activated carbon comes with a user manual that you must follow for the best results. The following steps should be usually followed while using the activated carbon:

Rinse the activated carbon with used aquarium water and wash off the entire dust and dirt. Avoiding this step may make the water cloudy.
Place the activated carbon in an area of high flow, for instance, filter or reactor. It will ensure that most of the water filters and the impurities strip out at the higher rate. This rate will be low if the activated carbon is placed in an area of low flow.

What is the replacement time of activated carbon?

On an average, an activated carbon will remain effective for about 3 to 6 weeks in freshwater and saltwater aquarium settings. However, this duration depends upon the dirt and impurities develop over time in the tank.

You should always place activated carbon in an area of high flow as it allows maximum filtration and removal of impurities, unwanted odor and colors. One thing that you should always keep in mind is using the mesh bags or filter pads properly for hold the activated carbon.

Sometimes the mesh bags get blocked by detritus and starts leaking traceable amount of nitrites, nitrates, ammonia and phosphate. To avoid it, rinse the mesh bags and filter pads each time you change the water. Follow it on a customized schedule for the best result. It will ensure that organics are not breaking or leaking down into the tank.

Final Words

Activated carbon is one of those aquarium accessories that can keep your tank clean, clear, odorless and free of impurities. The benefits of activated carbon often overweigh the few misconceptions many aquarists have. Activated carbon is a tried and tested filtration system which is effective in removing tannins and toxins. All you need is to buy one from a reliable store or from a trustworthy website.

If you have any queries about activated carbon or if you have faced any unusual experience with it, please feel free to share with us.

Mani

After completing her doctoral degree in Agriculture and working in various government and non- government funded projects, she settled to become a freelance copy and content writer. Born and brought up in the foothills of Himalayas she loves traveling and exploring the untouched. She is passionate about fish keeping and has got a good experience in the niche.

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View Comments

Jason Ross says:

November 12, 2023 at 5:14 am

How would activated charcoal/ resin react in a tight area of Aquarium water as the waters vaper as very moist air and not actual saturated water as when they use it in filters etc.. Because it is activated charcoal/resin and there are heavy metals and toxins in that gaseous water vapor, at so it would be expected there would be a reaction of some sort !!