Velda Cross-Flow Biofill Gebrauchsanweisung Seite 12

any filter material would be used with a too small porosity for water. It is recommended to replace
the active coal 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.
OPTION: UV-C UNIT
Unique to this filter is the option to install a UV-C Unit. Velda offers special 9 Watt and 18 Watt UV-C
Units for this filter. The unit can easily be placed in the holder (2). Replace the cap (5). The benefits
of UV-C are universally known: it makes green water clear and it is an excellent remedy in the fight
against bacterial infections. The Cross-Flow Biofill 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. Additionally, Velda also offers the Cross-Flow Biofill with a 9
Watt UV-C Unit already installed.
OPTION: HEATER
Instead of the UV-C Unit, a Velda Pond Heater 300 Watt can also be installed in the filter (2).
Replace the cap (5). This option is unique. The use of a heating element in the filter has three
important benefits:
1. The warmer filter water immensely activates the development of micro-organisms in the filter
material and also the biological breakdown of organic elements.
2. The filter can also be used in the winter months (to temperatures of -10°C).
3. If the outflow of the filter is the same height as the water surface, the pond will not freeze over
(to a temperature of -10°C) in this spot.
Besides the filter materials referred to above, Velda has filter media with specific properties:
l High active filter carbon to remover colourings and odours.
l Nitrate filter medium to absorb nitrite and nitrate.
l Ammonium filter medium to absorb ammonium and ammonia.
ITEMS FOR SPECIAL ATTENTION
If water should leak from the top of the Cross-Flow Biofill, this can be caused by pressure 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:
l The filter materials should have been place in accordance with the instructions for use.
l 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.
l The outflow orifice of the filter (50 mm) may not be reduced. The water must be able to flow
out freely.
l The maximum flow capacity of the filter is 5000 l/h. If the net output of the pump is larger, the
water will flow over the edge.
l Avoid back pressure. The water may not be elevated after the filter.
l Please take care, that the rubber ring in the groove of the cover has been applied correctly.
As Velda can not exercise any influence on a proper installation as well as the functioning of the filter
on the spot, Velda can not be held liable for any leakage, as a result of which the pond will loose water.
GUARANTEE
The Cross-Flow Biofill Filter is guaranteed by Velda for a period of 24 months after purchase.
See the terms on the enclosed guarantee card and visit www.velda.com/service for the war-
ranty procedure. In case you have a right to guarantee, the dated receipt has to be submitted.