Whether you are a novice aquarist or an experienced aquarist, you have surely heard of activated carbon. It is possible that you will use it in your aquarium, especially if you are a novice aquarist. But how is activated carbon made? What exactly is it for? Should we always have them in our aquarium? These are several questions that we will try to answer together in this article.

What is activated carbon?

Activated carbon is a filtration mass that we will be able to use in our aquariums and more precisely in our filters. Whether external or internal, whether settling filter or otherwise, we can use it in any filter. This filtration mass, we can find it in different forms: in granules or in chips… And we can also find it in foam impregnated with activated carbon.

But whatever the type, the efficiency remains the same and only the price will vary. This is because cans of activated carbon granules or shards are much cheaper than activated carbon infused foams. Why? Because activated carbon impregnated foams are usually sold by the manufacturers of your filter.

How to use it?

For example, suppose you have a JBL filter . You will have to buy JBL activated carbon foams provided for the reference of your filter. This one will adapt perfectly to its size and that is what makes its price. On the one hand, there is the brand, but also quite simply because you need to have a very precise foam according to the reference of your filter.

And the same goes for all activated carbon filter cartridges. They are obviously more expensive. They are easy to use thanks to the cushions filled with foam and the cartridges. The same goes for pellets. Just put them in a small filtration sock or nylon stocking. A quick rinse with tap water and you can put this filtration mass in your external filter, your settling tank or your small internal filter. So, if you hesitate between granules, shards and activated carbon cushions, simply take the cheapest activated carbon.

How is activated carbon made?

You might be wondering what activated carbon is and how it is made. Activated charcoal is vegetable charcoal, charcoal that has undergone a special treatment to activate it.

We are going to put this charcoal at high temperature and with phosphoric acid we are going to activate this charcoal to be able to make it more porous and even more absorbent. And to go even further, for chemistry enthusiasts in particular, know that activated carbon draws its absorption power from the malt sales force and more precisely from the dispersion force of London.

We can also note that activated carbon is not only used in aquariums, quite the contrary. It is also used in cosmetics, medical, water treatment, gas masks, cooking water and many other applications.

What will the activated carbon be used for?

Activated carbon is a so-called “chemical” filtration mass, not because it uses chemicals, but quite simply because it will chemically modify the water. It is an ultra absorbent filtration mass. It absorbs odors, colorings, chlorine and it will also be used to absorb the remains of medicines after a medicinal treatment to treat your fish.

Beginner aquarists will use activated carbon for two main reasons: to clarify the water so that the water is almost crystal clear and to remove any bad smells. A slightly more seasoned aquarist, on the other hand, will rather use activated carbon very occasionally, only to remove the remains of medication.

Do we have to use activated carbon all the time?

The answer is rather no. Activated carbon should not be used permanently in its filter. Why? First, because activated carbon, if it absorbs colorings, odors, drug residues… It also absorbs various trace elements that plants and fish use for their growth.

For example, if you want to use Catalpa de Latour leaves or even oak leaves to make an Amazonian aquarium with black water, you should not use activated carbon because all the tannins that will be rejected by the catalpa leaves or the oak leaves, will be absorbed by the activated carbon. Certainly, you will have clear water using these elements, but you will lose all the benefit of peat or catalpa leaf.

And also, even if it is always noted on the leaflets of medicines for fish, remove the activated carbon from your filter if you have it before doing the treatment on your fish, because otherwise the treatment will be immediately absorbed by the activated carbon and that will have been of no use. Once the treatment is finished, you can use activated carbon to remove the remains of the medication.

When should you change your activated carbon?

Activated carbon is not a filtration mass that we can keep all the time, unlike foams or biological masses.

We have it above, the action of activated carbon is to absorb elements. But obviously, after a while, the activated carbon is saturated and it can no longer absorb anything. On average, you can keep your activated carbon in your filter for a month before throwing it away or changing it. However, we cannot give a very precise duration since it will depend on what there will be to absorb in your aquarium as well as the quantity of activated carbon that you will put in your filter.

In practice, where should the activated carbon be placed in the filter?

You should already know that before putting the activated carbon in place in your filter, you must always rinse it with tap water in order to remove the carbon dust. In a small internal filter, it will simply be placed in the center of the foam while in a settling filter or an external filter, we will place it at the top.

Beginners in aquariums almost always use activated carbon in their filter because sellers advise them to use activated carbon to keep water clear and water odor free. But all this actually hides the mistakes of beginners, which often consist of putting too many fish in too small a volume of water. Buying activated carbon regularly will therefore solve the consequence, that is to say the odors and the color of the water, but not the cause which can very often be overcrowding.

Unfortunately, many pet store sellers advise their customers very badly. And this in order to sell a maximum of fish, regardless if the aquarium is too small and also to sell them activated carbon very regularly.

A healthy and balanced aquarium does not normally need permanent activated carbon filtration. If you have odors or if you have abnormal coloring in your aquarium, there is a reason and you must find the cause to solve this problem, activated carbon will only mask it.

There are still some typical cases where activated carbon has its uses, especially if you use mangrove roots as decoration in your aquarium. Indeed, these tend to release tannin and make the water rather yellow, sometimes for several months or even a year. And there, the activated carbon will help us to remove all this tannin which is not nice.

Special case: invertebrates and activated carbon

On some activated carbon packaging, you will sometimes notice a small symbol telling you that activated carbon should not be used with invertebrates, therefore mainly shrimps. So why couldn't activated carbon be used with invertebrates? This is because activated charcoal can be activated in two different ways.

As said above, activated carbon can be activated with phosphoric acid, but before we mainly used zinc chloride, and zinc is a residue that shrimps don't like at all and that can cause their dead.

So, when manufacturers tell you on the packaging that you shouldn't use activated carbon with invertebrates, it may mean that the carbon has been activated with zinc chloride, although this is used less and less nowadays. days.

Indeed, we increasingly use phosphoric acid, which is harmless to invertebrates. Afterwards, we cannot really know which method was used to activate the activated carbon. Manufacturers do not always necessarily have the idea of ​​putting a small label to warn of dangers. So, as a precautionary measure, it is better to avoid using activated carbon in aquariums where you have shrimp or invertebrates that you care a lot about or have paid a lot of money for.