UV Clarifiers

Green, pea-soup water is caused by tiny free-floating algae that a normal filter can't catch. A UV clarifier fixes it. As water passes the ultraviolet lamp, the algae clump together so your filter can remove them, and the water usually starts to clear within a week or two.

Our UV clarifiers

Choose a stand-alone Pond One Cleartec UV clarifier, from 5W for small ponds and water features up to 36W for larger ponds, and plumb it in between your pump and filter. Or choose a pond filter with UV built in, such as the Pond One Claritec, Laguna PressureFlo, Oase Filtoclear, Oase Filtral or Oase BioPress sets.

Choosing the right wattage

The bigger the pond, the more UV wattage you need. Size up for ponds in full sun or with lots of fish, and make sure your pump flow suits the clarifier. Water that passes too quickly won't get enough UV exposure.

Keep it working

UV lamps lose strength over time even while they still glow, so replace the bulb every 12 months, ideally in spring. Clean the quartz sleeve at the same time. You'll find replacement UV bulbs and quartz sleeves for Pond One, Blagdon, Laguna and Philips units.

A UV clarifier treats green water but not string algae. For that, see our algae control treatments. Read more in why your pond water is green and how UV clarifiers fix it.