appropriate groove and close the filter with a fastening clamp. It is recommendable,
before closing the cover, to fill the filter with water.
Connecting the pump
The filter has a 32/40 mm hose connector for the intake opening. To prevent capa-
city loss, the hose connector must be sawed off to the diameter of the pump hose.
A flexible reinforced hose is recommended. Attach the hose with a fastening clamp.
Velda recommends using a minimal 2500 and maximal 5000 litres per hour pump.
The recommended pump is High-Stream 4500. These strong low-energy pond
pumps from Velda provide proper flow. They are maintenance friendly. The out-
flow swivel of the filter is 50 mm. Firmly tighten it with the jam nut in the outflow
opening of the filter. Use a suitable flexible hose here and secure this with a hose
clamp. To prevent leakage problems, the outflow opening should not be reduced.
MAINTENANCE
If the water output of the filter decreases considerably or if the lid is leaking, the
cassettes with filter material must be rinsed out. It is generally enough to rinse it
several times with tap water. The fastening clips have been constructed in such a
way that they will spring open when the pressure in the filter will become too high.
This will occur for example, if the filter material should contain too much dirt or if
any filter material would be used with a too small porosity for water. It is recom-
mended to replace the active carbon and nitrate absorbing filter medium once or
twice a year, or at least, at the start of the new pond season. If the water supply to the
filter is stopped for four or more hours, the filter material must first be rinsed before
filtration resumes. This prevents the micro-organisms which die from an oxygen
shortage from getting in the pond. It is recommended to use Bacterial Filterstart.
UV-C UNIT
The built-in UV-C Unit 18 Watt supplied along is able to keep 10.000 litres of pond
water crystal clear. The unit can easily be placed in the holder. The UV-C lamp re-
moves floating algae (green water) and it is an excellent remedy in the fight against
bacterial infections. The Cross-Flow Swirl has a separate compartment, meaning that
the UV-C radiation does not come in contact with the filter material. Therefore, the
micro-organisms in the filter material are not damaged. The unit has a transparent
screw cap for safe inspection of the lamp. See also the UV-C Unit instructions.
Besides the filter materials referred to, Velda has filter media with specific properties:
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Norit high active filter carbon to remove colourings and odours.
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Ammonium filter medium to absorb ammonium and ammonia.
ITEMS FOR SPECIAL ATTENTION
If water should leak from the top of the Cross-Flow Swirl, this can be caused by pres-
sure building up inside the filter, as a result of which the water can not flow freely.
Below you find some items which will help you finding out why the filter is leaking:
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Place the filter above the level of the pond water and horizontally on a flat soil.
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Place the cassettes and filter materials in accordance with the instructions for use.
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Inspect whether the filter material is blocked up or polluted. Especially if the
pond water was/is considerably green, the filter material can quickly get polluted
and it has to be rinsed then.