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One
of the most important pieces of equipment for any Koi
Enthusiast, unless they particularly like 'Green
Water' and don't wish to be able to see their
prized possessions, is....
The
Ultra Violet Sterilizer !
HOW
DOES A UV FILTER CLEAR GREEN WATER ?
Single-celled
green algae require light and nutrients to thrive. Sunlight,
unless the pool is in a shaded spot or protected by a pergola or
overhanging plants, works with nitrates to bring on bloom,
sometimes in a matter of hours. The small diameter of the
Chlorella vulgaris cells means they can pass through all
conventional filter media and all but the finest open-celled
foam, so physically filtering them out in their normal form is
next to impossible unless the medium is partially blocked.
However, passing the cells through a UV disrupts their internal
structure, if not actual killing them, so that they clump
together or 'flocculate'. These clumps, being of a relatively
large diameter, can be trapped and broken down by the filter.
WHEN
TO USE A UV ?
Most
Koi keepers will keep their unit(s) switched on 12 months of the
year. But the owners of small garden ponds may just find that
only in the spring, with the combination of longer days and an
upsurge in fish activity (and, therefore waste production) is UV
necessary. If you intend to run your UV year-round, it must be
protected from frost in a well-ventilated housing. Again the
recommendations vary depending on the manufacturer, some
suggesting that the unit be dismantled and stored dry over
winter.
HOW
MUCH UV DO I NEED FOR MY POND ?
Purely
for green water eradication, 8-10 watts per 1,000 gallons is
usually recommended, but some pond keepers will maintain that,
for a reduction of bacterial levels, this can be increased
threefold to 30 watts. However, this is an oversimplification.
Pond capacity is not the only factor to take into consideration
- stocking levels, how much sunlight the water receives and the
amount of shading will determine which size UV is right for you.
CONTACT
TIME
Obviously,
for maximum efficiency, you should run our UV in conjunction
with a pump rated in gallons per hour to suit the size of your
pond. The longer the contact time of the water with the UV
light, the more algae spores will be treated, but there is a
lower limit to the throughput of water, beyond which filter
efficiency and/or aeration via the Venturi may suffer. If your
pond has only on UV and one run of return pipework, you may have
to compromise, on the basis that the pump must circulate the
entire pond volume once every two or three hours (as an example,
a 1,000 gallon pond should be teamed with an 8-15 watt UV and
pumping rate of 500 gph minimum). One way of irradiating a large
pond with only one UV is to T-off some of the flow through the
unit. This treated water need not necessarily be returned direct
to the main body of the pond - it can be diverted back into the
filter. If you have two UV's plumbed in parallel, servicing the
same pond, you can effectively double the contact time in each
UV unit and substantially increase the amount of irradiation.
The latter is a useful option in very large ponds, and
manufacturers may offer tandem conversion kits, enabling you to
'bolt on' one or more UV's.
Bearing
in mind what we have mentioned above - Using the correct size
U.V. not only clears 'Green Water' but also enables you to
be able to view your Koi in Crystal Clear Water, and as the term
'Sterilizer' infers, it also sterilizes the water itself - thus
helping to kill the harmful Bacteria that lives in the water and
which cause problems to our valuable Koi - So a correct size
U.V. is beneficial all round.
Using
any U.V. not only clears 'Green Water' but also enables
you to be able to view your Koi in Crystal Clear Water, but, as
the term 'Sterilizer' infers, it also sterilizes the water
itself - thus helping to kill the harmful Bacteria that lives in
the water and which cause problems to our valuable Koi - So
using the correct size U.V. is beneficial all round.
At
THE EAST RIDING KOI Co. we use and recommend the U.V's marketed
under the Brand Names of 'YAMITSU' and 'POND-CLEAR''
- both of these manufacturers have an excellent reputation and
their products are both reliable and well made - there are of
course many other manufactures who all produce 'Good &
Effective' U.V's which we will obtain for you if you would
prefer them .... Just let us know what it is you want .... OK
The
U.V's come in various Sizes - From just 6 watts right up to 240
watt. The size you require depends on the amount of water in
your pond or tank.
In
The Yamitsu Range:
As a
guide: 10 watts will be sufficient for a pond with 1,000 gals -
60 watt = 6,000 gals, so you can work it out from those examples
on what size of U.V. you require. The Yamitsu range covers UV's
from 6 watts right up to 240 watt.
In
The Pond Clear range
Providing
we are talking about a correctly filtered 'True Koi' pond -
then, again as an example, the 55watt U.V. will adequately cope
with a pond up to a maximum of 10,000 gals. Pond-clear do
manufacture smaller units.
And
as you would expect: we keep a full range of spare 'Tubes' and
certain other spare parts.
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