Author: Dr. L.E. Freese
There
are different filters available at various prices and it is advisable
that the filter is not only bought for its affordability, but because it
is suitable for the aquarium setup that you envision and that the
maintenance that is required suits you.
Firstly one must decide if
you would prefer a motor driven, air driven or a trickle filter and
should it be external, internal or undergravel? Each method of
filtration has its pros and cons and these need to be weighed up before
you purchase one and find that it does not suit your needs.
The capacity that is needed
varies depending on the size of the aquarium and the waste load. The
capacity of a filter is determined by the volume (of the filtration
media) and the turnover rate (rate at which the water flows through the
filter) of the filter in relation to the size of the aquarium and the
amount of waste produced by the occupants. Excess volume does no harm,
but if the volume of media is insufficient the filter clogs up very
quickly and this leads to an increase in maintenance requirements. If
the turnover rate is too high the turbulence in the aquarium increases
and this leads to increased level s of stress in the fish. On the other
hand cloudy water and insufficient filtration is the result of a
turnover rate that is too low.
In container filters (canister, box or trickle)
where no specific media is required, different media can be used
depending on what type of filtration you require. There are 3 basic
filtration methods and they have different media which are suited for
these functions.
1)Biological
– Media provides a home for the bacteria of the nitrogen cycle
2)
Chemical – Media reacts chemically with the elements in the
water and thus changes the pH, salinity, hardness of the water or
removes pollutants
3)
Mechanical – Media removes suspended particles in the water and
this ensures clarity
CHEMICAL FILTRATION
Calcium Carbonate – Hardens
water and increases the pH of the water. This media can be washed and
reused.
Carbon – Removes certain
medications, heavy metals and chemical contaminants from the water by
absorbing them and therefore it needs to be replaced frequently.
Zeolite – Neutralises
ammonia through an ion exchange process and needs to be replaced and it
should only be used as an emergency media not as a replacement for the
biological breakdown of nitrates and nitrites in the water.
MECHANICAL AND BIOLOGICAL FILTRATION
Media that is used for mechanical filtration is most
often used for biological filtration.
Ceramics – Porous and in
various shapes which are generally used as biological media.
Filter wool/floss – Cheap
and can be washed and reused. The problem with this media is that it
tends to clog up quickly and needs to be washed fairly frequently.
Foam – A very efficient
mechanical and biological filter media, which can be washed and reused.
It can be bought in different porosities, which makes it more versatile
than other media and water flow through the foam is uniform and thus a
greater surface area is available to the bacteria. Make sure that the
foam is filtration media, as mattress foam clogs quickly, is not easy to
clean and may contain chemicals that are toxic to fish.
Gravel – It must be
aquarium gravel and not sand (clogs easily). Washing is not so easy but
it can be reused indefinitely.
This is only an overview of
filtration and its media, it cannot be stressed enough how important it
is to do a little homework and find the filtration system that will
enhance your aquatic pleasure
September 2001
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