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Allotment Articles1.
Allotment Articles 2.
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Ultra Violet
Sterilizers
Interest in fishpond filters has grown enormously in the last few years. People not only want to add them to their ponds, but where they already have them installed they want to improve their effectiveness in keeping the water clear and healthy.
The biggest thing to affect filtration is the Ultra Violet Sterilizer. These should not be confused with filters as they do a completely different job. A standard UV system consists of a quartz sleeve into which fits a fluorescent tube. Instead of emitting white light the tube gives out light only at the ultra violet end of the spectrum. As this radiation is extremely harmful to living tissue and eyes causing cataracts and skin cancer the whole assembly is shielded with a casing. Water is then pumped through the quartz crystal tube so that the UV light shines on to it. This sterilizes the water as it passes through killing the bacteria, parasites and algae thus making the water free from disease, as well as making it much clearer. The action of the UV system also causes the particulate matter to flocculate. This means that the suspended muck particles gather together in clumps making it easier for the filter to remove them and thereby becoming more efficient.
A biological filter is still needed even with a UV in operation because the UV does not remove the ammonia, or nitrates from the water. If you didn’t have a filter you would still get clear water, but after a period of time it would become poisonous to the fish with a build up of chemicals unless you carried out regular, partial water changes. UV systems are quite expensive to buy, but prices are coming down. Because they use a fluorescent tube they do not cost much to run, but the tube has to be replaced every season as it becomes less effective with time. Also every couple of years the quartz sleeve has to be replaced as it becomes scarred and pitted making it opaque. As with any other light fitting using a fluorescent tube, the starter motor also has to be replaced every few years. UV’s are available in several different sizes suiting pools ranging from 100 gallons to mini lakes holding several thousand gallons.
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