What is a UV Clarifier and how do they work

UV Clarifier

A UV Clarifier (UVC) is used in conjunction with your filter system, its main purpose is to remove single cell algae that turns your pond water green.

Green pond water can be a real problem, it’s caused by single cell algae (Chlorella Vulgaris) that once they start forming in your pond will multiply and spread really quickly, this can be paticularly bad in the spring and summer months.

Green water not only looks unsightly but can deprive your fish and plants of vital oxygen and nutrients, the main ingredients of the algae diet.

The strange thing is, it’s a sign that your pond is healthy, single celled algae need light and nutrients to thrive, so if your pond has plenty of light and lots of nutrients its healthy, but it’s also the perfect breeding ground for the algae.

A UV Clarifier ( Ultra Violet Clarifier ) is fitted into your filter system to control and remove single cell algae giving you crystal clear water. It can be used as a stand alone unit or can be built in to your filter system.

A UVC consists of a chamber that holds a UV lamp, there is an inlet that the pumped pond water enters, the pond water passes over the UV Lamp and exits via an outlet. The inlet and outlets usually come with stepped sizes for different sizes hoses.

The UV lamp is protected by a quartz tube so the electrics don’t come into contact with any water and you often find a viewing window to check if the lamp is working so you don’t have to take it apart to check.

They are available in various sizes to suit the size of your pond, each one being measured in watts which is the lamp size.

They have replaceable UV Lamps which will need to be renewed at least once a year, we suggest you replace your lamp at the start of spring.

How does a UV Clarifier work.

Single cell algae are so small they can pass straight through a conventional filter system without being filtered out.

However this is where the UVC comes into play, passing the single cell algae over the UV lamp disrupts their internal structure, destroying their ability to multiply and makes them clump together.

Once they have clumped together they are big enough to be removed by your normal filtration system.

A UVC can be fitted anywhere within the filter system, at the start so that the mechanical filter will remove the algae, in the middle where the biological filter will deal with the cells or at the end of the filtration system where the clumped cells are pumped back into the pond, they will then be filtered out in the next cycle.

If you want to buy one check out our guide Best UV Clarifier for a garden pond.