How Often Do I Need to Change My UV Bulb?

A germicidal UV bulb produces ultraviolet radiation which helps to kill pathogens and single-celled algae but all bulbs have a service life as this radiation slowly deteriorates during use.  Most bulbs used in ‘off the shelf’ pond filter systems and stand-alone UV Clarifiers have a service life or around 12-18 months so should be changed before this period elapses. Water Garden generally recommend changing the bulb once a year, usually at the start of the season to ensure the clarifier performs to the best of its ability.  

If your pond is purely ornamental and doesn’t contain fish, you should be fine to change the bulb after 18 months of use.  Many avid Koi keepers change their UV bulbs far more frequently (6-12 months) as it is important that the fish can be seen in gin-clear water to display the wonderful colourations of these highly attractive fish breeds.

More professional UVCs such as the OASE Bitron Eco utilise bulbs which offer longer service lives and the technology will inform the user when a bulb requires changing.  Commercial UVCs often use powerful Amalgam lamps but again, these need to be changed at a similar frequency to a standard lamp (but at a significantly higher cost).

Try to use the manufacturers branded spare bulbs. These may be more expensive than non-branded replicas but ensure quality.  Non branded bulbs are very unlikely to have been produced to the same exacting standards and may, in fact, offer little or no germicidal benefit whatsoever.  Just because a bulb glows blue, does not mean anyone is home!