Use activated charcoal after medication
Carbon filtration is used to remove chemical residues and organic matter from aquarium water. Filtering with activated charcoal can therefore be useful if residues of medication have to be removed from the aquarium. Drugs can even be removed from the aquarium faster with activated charcoal than with water changes.
Otherwise, filtering with activated carbon is not necessary.
Use activated charcoal when setting up new
Activated charcoal is sometimes recommended when setting up new aquariums.
Activated charcoal makes sense when setting up new equipment:
- Plastic parts, hoses, etc. give off plasticizers and other residues that are filtered out by the carbon.
Activated charcoal does not make sense when setting up new equipment:
- Plasticizers from plastic parts are already decomposed by bacteria during the running-in period.
- Water changes remove any residue from plastic parts.
- A smoker in the room puts more strain on the aquarium than plastic parts.
Experience has shown that activated carbon is not necessary when starting an aquarium.
Use activated charcoal if the water has a yellow tinge
Fulvic acids can cause the aquarium water to turn yellow. With good activated carbon, the yellow tinge can be eliminated excellently. However, the yellow cast is completely harmless.
Duration of use
Activated carbon is exhausted after a short time, according to some reports after 24 hours. According to other data, activated carbon can be used for 14 days.
It is often mentioned that oversaturated activated carbon releases at least part of the absorbed substances back into the aquarium water. It is unclear whether this is really the case and which substances can be released again and how quickly.
Other sources write that substances that have been absorbed are not released again. After that, activated carbon is no longer active after 14 days, but still works as a normal mechanical filter. Because activated carbon is usually used after the biological part of the filter, the biological filtering is not affected.
It is usually recommended that activated charcoal should only be used for 2 to 3 days and then discarded.
mode of action
Activated charcoal acts like a sieve. Particles above a certain molecular size are retained. Because most medicines have very large molecules, they get caught in the activated charcoal. Small ions such as nitrite and nitrate are not filtered out. So activated carbon filters relatively randomly by size.
Activated charcoal can mess up the chemistry of the aquarium water, especially the trace elements. Some types of activated charcoal give off large amounts of zinc, which can cause poisoning.
manufacturing
Activated carbon is produced by heating up to 800° C in the absence of air. Coconut is said to be particularly suitable. Unfortunately, phosphoric acid or some phosphate is sometimes used as an auxiliary agent.
The coal is ground with zinc chloride, mixed and pressed. The zinc chloride prevents the coal from sintering. Zinc chloride is basically a temporary filling material for the later pores.
The zinc chloride is dissolved out of the coal again with water. There remains a myriad of small caves in which the zinc chloride was.
This activation increases the active surface of the carbon. i.e. the places that can filter are increased.
The size of the pore size determines which molecular sizes can be adsorbed as well as how much and how strongly can be adsorbed. Capillary action is also important.
Good activated carbon can absorb up to 50% of its own weight in organic matter.