The Weald Aquatics Blog - How to clean and change a pressurised pond UV light filter - another blog post from Weald Aquatics | Aquarium & Pond Fish Shop in Kent


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How to clean and change a pressurised pond UV light filter

Blog post written by Gary | 04 September 2014 | Category: Pond maintenance


Many customers find that even when they have a UV light filter fitted to their pond filter system the pond water remains or still goes green with algae. If the UV light filter is the correct size for the pond, then normally if the unit is working either the UV lamp needs replacing and/or the quartz glass has become dirty reducing the amount of UV radiation reaching the algae allowing the algae to multiply very quickly.

The UV lamp should be replaced every year, ideally in the spring, giving full radiation output throughout the spring, summer and autumn when the sun is at its strongest. When changing the lamp it is best to inspect the quartz sleeve for a build-up of hard water deposits and dirt. This should be cleaned from the quartz glass carefully as the glass sleeve is very fragile.

We have taken a series of photos to show how a Bermuda pressurised UV filter is dismantled ready for a lamp change. To change the UV lamp in a similar filter system will normally follow the same rules.

Changing a lamp

Turn both pump and UV filter off at the mains switch before opening the filter.


The UV lamp can be changed with the lid in the closed position.
Remove screws on ring, turn ring to allow UV cover to be removed.


Unscrew UV lamp housing to reveal UV lamp, remove lamp by gently pulling out of the electrical connection. Insert new UV lamp by pushing gently into the electrical connector.
Screw back UV lamp housing making sure the O-ring is in position, re-assemble top dome by screwing back into position. Turn pump and UV light on. The UV light can be checked when switched on by looking at the clear hosetail – a blue glow will be visible when the UV lamp is operating.