The Weald Aquatics Blog - UV Filtration for aquariums and ponds - another blog post from Weald Aquatics | Aquarium & Pond Fish Shop in Kent


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UV Filtration for aquariums and ponds

Blog post written by Gary | 14 November 2013 | Category: Aquarium and pond equipment

It has been known for a long time that UV light of a certain wavelength has germicidal properties. The wavelength between 200nm (nanometers) and 280nm is UVC radiation and the wavelength of 254nm (or if you want to be exact 253.7nm) is the most efficient at destroying or severely disrupting most micro-organisms.

We have two types of products which use UV lamps: an aquarium sterilizer and a pond clarifier. Both have the same UV lamps but are used to solve different problems.

The aquarium sterilizer is set up to destroy many organisms including fungal spores, some bacteria, protozoans, viruses, Oodiniun and Cryptocaryonin found in marine aquariums. A UV sterilizer is usually installed in the return pipe back to the aquarium from an external filter as any dirty water or discolouration of the water will interfere with the treatment of the water.

There are many benefits in fitting a UV sterilizer to an aquarium especially a marine aquarium:

  • It reduces bacteria and pathogen levels and helps to keep Whitespot in check.
  • It helps the introduction of new fish.
  • It improves water quality.
  • It reduces the risk of any disease spreading.

A pond clarifier works in the same way as the aquarium sterilizer in using a UV lamp, however it is set up to primarily to destroy waterborne algae giving a crystal clear pond.  The pond UV unit can be installed before or after the filter or in some installations just the UV unit without a filter system, with the pond water being pumped through and back into the pond.

UV lamps should normally be replaced every 6 months (4000 hours) in an aquarium sterilizer and 12 months (8000 hours) in a pond clarifier. When changing lamps the quartz glass which protects the UV lamp should be cleaned to maintain optimum performance of the unit.

UV radiation is dangerous; never look directly at an illuminated UV lamp.


An example of an aquarium UV sterlizer
An example of an aquarium UV sterlizer
An example of a pond UV sterlizer
An example of a pond UV sterlizer