Velda Clear Control Mode D'emploi page 17

ments that are necessary for the biological and chemical processes in the pond envi-
ronment. If all values are correct and the micro-organisms function well, it can be said
that there is a biological equilibrium. For many ponds, filter equipment is an essential
tool, because often too many fish are kept in proportion to the quantity of pond
water. In a garden pond a fish has far less water at its disposal than in the wild and the
natural equilibrium will be attacked more quickly by the many excrements that are
produced by the fish. This is certainly the case with Koi. Filters serve two important
functions: the water is kept clear by filtration and circulation creates a sufficient
amount of oxygen. The filter can be used for both mechanical and biological
purposes to filter the water. Below a short description will be given of both methods.
MECHANICAL ACTION
The action of a mechanical filter is based on the removal of organic and inorganic
dirt particles and, if necessary, the removal of colourings, depending on the filter
material. In order to prevent the filter material from getting silted up, it should be
rinsed regularly. Normally this is an annoying job, but it can easily be done when
using the Velda Clear Control pressure filter.
BIOLOGICAL ACTION
A basic assumption of a biologically functioning filter is to obtain a better and
quicker conversion of organic components by means of micro-organisms. An in-
tegrated biological filter benefits the general activity of the micro-organisms and
consequently stimulates the growth of the water plants. It is advisable to use a
biofilter when stagnating plant growth, excessive growth of algae or a too large
fish stock in proportion to the quantity of water, are at stake. Initially the filtration
will be exclusively mechanical, however, with the lapse of time, the materials will
become biologically active. You can stimulate the biological action of your pond
by inoculating the filter substrates with a special culture, like Bacterial Filterstart
GUARANTEE
Except for the rubber ring, fastening clamp, hose swivels and filter materials, this
Clear Control pressure filter is guaranteed by Velda for a period of 24 months.
In case of wrong assembly, injudicious use (of the 7 position valve), damage due
to frost or bad maintenance, the guarantee will cease. This also applies in case of
use of the filter in combination with oil, petrol or lubricants. If a claim to guarantee
can be laid, a dated receipt should be presented. See the terms on the enclosed
guarantee card and visit www.velda.com/service for the warranty procedure.