nisms, and the condition of the fish. The water must then also contain all the elements
that are necessary for the biological and chemical processes in the environment.
If all the values are good and the micro-life function well, then there is a biological
balance. A filter installation is a solution for many ponds because often, too many fish
are kept in relation to the volume of the pond water. In a garden pond, fish have much
less water at their disposal than in nature, while the natural balance is also quickly
affected because the fish produce a lot of waste. This is definitely the case when
keeping Koi-carp. The water can be kept clearer through filtration, and the water
circulation ensures enough oxygen. The Cross-Flow Swirl can be used mechanically
as well as biologically to filter water. A short description of both methods follows.
Mechanical working
The working of a mechanical filter is based on removing organic and inorganic
waste particles and - depending on the filter material - removing colour particles.
To prevent the filter material from becoming silted up, it should be regularly rinsed
clean. This normally tedious task is as easy as rinsing the cassettes filled with filter
materials with tap water.
Biological working
The basis of a biological working filter is to obtain a better and quicker conversion of
organic elements through the use of micro-organisms. A biological filter promotes
the general activity of micro-organisms and by doing so, stimulates the growth of
water plants. Use of biological filtration is recommended when there is stagnant
plant growth and/or extreme algae growth. Initially, the filtration will be exclusively
mechanical, but over the course of time, the material becomes biologically active.
The biological working of the filter is stimulated by the inoculation of the filter
material with a special bacterial culture, such as Bacterial Filterstart.
THE CROSS-FLOW SWIRL
The Cross-Flow 'Swirl' with filter cassettes and 4 sophisticated filter materials, is based
on the flow principle. The water is passed along a standard UV-C Unit of 18 Watt,
through the various filter materials. The UV-C Unit ensures an effective treatment of
floating algae and any germs present. New and spectacular is the use of a nitrate
reducing filter medium. It is a glass-ceramic material with extremely fine pores,
which is capable of absorbing nitrates. This nitrate filter medium is placed in the
rotating holders (swirls), as a result of which the water treatment is optimum. The
filter also contains a cassette with highly activated filter carbon, a cassette with a
Japanese mat and a holder with fine filter foam. The cassettes with filter material can
be rinsed in a trice. All in all, the UV-C Unit and the sophisticated filter materials, this
Cross-Flow Swirl provides crystal clear and healthy pond water. Suitable for ponds
containing up to 10,000 litres of water.
INSTALLATION
The Cross-Flow Swirl contains 3 removable cassettes and a holder for filter foam.
The filter comes complete with all the necessary filter materials. Carefully rinse the
filter materials before use. Use the enclosed net for the filter carbon. Release the
swirls and fill them at the bottom side with the nitrate filter medium. Place the lid in
the correct position on the filter, ensuring that the connecting ring is placed in the
