UVCs are installed into pond filtration systems to help stop the pond water from turning green.Green water is caused by single-celled algae, a microscopic plant, which is suspended in the pond water. Suspended algae are so small that they can pass through even the finest foam layers or polishing pads. When exposed to the strength and frequency of ultra violet light emitted by a UVC the algae’s cell wall is damaged. This kills the algae and causes the separate algae cells to flocculate, or clump together.

These clumps of algae are large enough to be caught up in the filter’s foam layers, and can be removed from the pond water. It is vital that the UVC unit is used in conjunction with a mechanical filtersystem so that the flocculated algae can be caught.UVCs do not kill algae which are not exposed directly to the UV light, so blanketweedand algae attached to pond walls are not harmed.

Also, UVCs do not kill bacteria and viruses to any significant level. Ultra Violet Sterilizers (UVSs) are available; these models emit a much higher radiation level than given off by UV Clarifiers, this level of UV light will kill almost all bacteria. However, when adding pond bacteria it is good practice to turn off a UVC for a few days so that the bacteria cultivation is not impeded at all. UVC bulbs give off UV light for around six to nine months if used continuously.

After this period the bulb may still glow, but the amount of UV light it gives off will be reduced. It is advised that you should replace your bulb every springto ensure that the unit is working efficiently during the spring and summer months, giving off UV light when it is needed the most.

When changing the bulb you should try not to touch the glass part with your bare hands. Grease or dirt from your finger prints, when subjected to UV light, will burn onto the bulb. This leaves dark spots which will block the UV light from passing out of the bulb, and can even cause the glass to corrode, damaging the bulb. 

Holding the bulb with a dry cloth or tissue when inserting will help to prevent this, and sustain the longevity of the bulb.The water pushed through a UVC unit is passed over a quartz sleeve. The quartz insulates the bulb from the pond water and allows the UV rays to pass through. When maintaining the unit it is important to clean the sleeve, as any build up of dirt will block the UV rays from passing into the water. 

Take care when removing and inserting the quartz sleeve, as it is very brittle and can be expensive to replace.UV Clarifiers are enclosed units. They are manufactured to withstand different water pressures, which is indicated by the models maximum flow-rate. 

The maximum flow-rate shows the largest size of pumpwhich you should use with that particular model.The UVC’s wattage gives an indication to the amount of UV light that the bulb emits.

Both the maximum flow-rate and the bulb type are calculated by the manufacturer to correspond to the size of the pond to which they are designed to treat. UVC units are installed into most Box, Pressurised and All-in-one filter systems, again the bulb’s size is in proportion to the amount of water intended to be treated.