Activated carbon is one of the most commonly used «chemical» filter materials in the aquarium. Thanks to the use of activated carbon, we achieve that the aquarium water is free of chemical impurities.
Activated carbon for aquarium filters
What is activated carbon and what is it used for in the aquarium?
Activated carbon … surely you have heard or read on occasion that activated carbon is a product that is used in the aquarium.
But surely, at this time you will be wondering what activated carbon is, how and why it is used in the aquarium. I hope throughout this article, to clarify all the doubts that may arise about this filter material .
Activated carbon is a filter material that absorbs, like a natural sponge, all kinds of chemicals that can be found in aquarium water, such as heavy metals, phosphates, nitrates and drug residues or toxic elements.
When we talk about coal, we can refer to two types: mineral or vegetable.
In the case of activated carbon, its origin is vegetable, that is, it comes from the partial burning of different types of wood.
To be effective in filtering water, it is subjected to a pulverization process into grains of up to two millimeters.
As a material, activated carbon is very porous. It is precisely this characteristic that makes it an ideal filter material, since by forcing the water to pass through it, many of the chemical components present in the water are trapped inside the carbon.
It is common to find it as one of the filter materials, inside the filters that perform chemical filtering.
Charcoal is the best product to purify and deodorize aquarium water , completely eliminating micro-toxins and pheromones. You just have to understand how it works and how it can be useful.
Chemical filtration and activated carbon
The most complete aquarium filters perform three types of filtration in an aquarium: mechanical, biological and chemical.
Activated carbon is within the third filtering process (chemical), which means that with its use you will eliminate most of the chemicals present in the water, including chlorine.
How is charcoal activated?
Charcoal is generated by heating wood and plant residues at temperatures ranging between 400ºC and 700ºC, in a total absence of air.
With this process, it is possible for plant materials to change their molecular structure, having, thanks to this process, a high carbon content … approximately 98%.
During heating, water vapor or carbon dioxide is injected, seeking that the carbon increases its porosity to the limit, thanks to the carbon molecules are oxidized.
In addition to adding water vapor and / or carbon dioxide, some manufacturers include hygroscopic substances, such as zinc chloride, to increase the absorption capacity.
This small modification in the production process of charcoal, by causing the oxidation of its molecules, is what is called activating the charcoal.
How is activated carbon used in the aquarium?
Activated carbon is used as a chemical filter material within aquarium filters.
Depending on the manufacturer and the type of filter that we use, it has different presentations. Some filter manufacturers have cartridges that do not allow any type of manipulation, only an old cartridge is exchanged for a new one.
However, many aquarium filters allow you to use activated carbon in bulk.
For its use, very thin bags are sold, which allow to contain the activated carbon and that the granules do not end up inside the aquarium.
A practical substitute is to use a fine-grained sock.
Once we have the activated carbon in our sachet, we will proceed torinse it repeatedly to remove any dust it may contain.
When we have it clean we place it in the filter. It is usually placed in the last position, behind mechanical materials (sponge, perlon …) and biological ones.
How much coal do you have to use at a time?
The amount of activated carbon that we must use in our filter will depend on the variables of the aquarium: number of fish , the size of the aquarium and other factors that may depend on the moment, how it is that we have finished a process of medication, cleaning …
The best is to test if the amount of carbon used has been correct , once we start to use it.
And how can we know? Well, using methylene blue.
To know if the activated carbon filter is doing its job properly, we will place a few droplets right at the entrance of the filter or inside the filter itself.
If the charcoal is doing its job correctly, the water should come out clear and crystalline, on the contrary, if it is not filtering well, there will be remains and the water will have a slightly bluish color.
How long is it effective?
The useful life of activated charcoal is another issue that often worries the most novice, since they do not know how long the effect can last.
According to experts, the properties of activated carbon are very changeable.
We can resort to the methylene blue test to find out the effectiveness of the carbon that we have installed in the aquarium.
As a rule, it should be changed after a month, after that period its effectiveness as a filter material drops a lot.
When is it better not to use activated charcoal?
The key for your aquarium to be in perfect condition is to identify the exact moment to provide any type of care, making changes aimed at improving the aquarium’s habitability.
Active carbon can always be used as a filter material, since it is a very absorbent material that will eliminate many chemicals, which are otherwise very difficult to remove.
But… of course, there are times when we introduce chemicals on purpose, like when we treat any type of disease.
In these cases, it is convenient to remove the activated carbon for the duration of the treatment , since it would not be totally effective.
Once finished, then the best and convenient thing is to put it back, so that it eliminates the remains of chemicals or medicines that may remain in the water.