UV lamps and UV-C sterilizers for ponds

A UV-C lamp for ponds helps limit green water caused by suspended microscopic algae. Installed in a suitable circuit, a UV-C clarifier complements the mechanical and biological filtration of your pond.

Discover our UV-C devices for small ponds, goldfish ponds, koi ponds, and large volumes.

To choose the right model, take into account the water volume, the actual flow rate of your pump, the sunlight, and the fish population. Our sizing guideline is 3 to 4 W of UV-C per m³, prioritizing 4 W/m³ for a very sunny or heavily stocked pond. Always check the manufacturer's recommendations and the device's allowable flow rate.

Do you already have a UV-C device? Check out our replacement bulbs, quartz tubes, and compatible parts.

How to choose a UV lamp for a pond?

• Power: allow at least 3 W of UV-C per m³ of water, more in full sun or with koi. The range covers both small ponds (Pond Clear UV-C 9W) and large volumes (Bitron Eco 240W).
• Lamp type: compact PLs for small and medium ponds (Vitronic, Bitron C), TL and T5 for larger volumes (Pro Clear Ultima, Koi Pro RVS, Power UV-C), amalgam for the highest power (Air-Aqua, Koi Pro Module).
• Installation: in line between the pump and the filter for most models, submerged for Air-Aqua amalgam devices, or for preliminary treatment before a gravity filter (Bitron Gravity, Bitron Premium).
• Flow rate: the water must pass slowly enough in front of the lamp: respect the maximum flow rate indicated on the device's data sheet.
• Maintenance: the bulb loses efficiency over time: plan to replace it every year at the beginning of the season and clean the quartz.

UV-C power guidelines (at least 3 W per m³):

These values correspond to the low end of our guideline of 3 to 4 W/m³: for a very sunny or heavily stocked pond, aim rather for 4 W/m³ and respect the manufacturer's flow rate indications.

Frequently Asked Questions

What is a UV lamp for in a pond?

The water passing in front of the UV-C lamp is treated; fine particles clump together and are then retained by the filter. Combined with properly sized filtration and plants, it helps the pond regain clear water: suspended green algae recede when balance is restored.

What UV power for a 10 m³ pond?

At least 30 W of UV-C, and rather 36 W or more if the pond is in full sun or houses koi.

When to change the UV bulb for a pond?

Once a year, preferably in spring when restarting. The bulb continues to light up, but its UV-C radiation decreases with operating hours.

Should the UV be turned off when adding bacteria?

Yes. Turn off the UV-C during bacterial treatment, for the time indicated on the product, to allow the bacteria to settle in the filter.

Where to install the UV-C device?

Most often between the pump and the filter, sheltered and accessible for maintenance. Some models are placed submerged or upstream of a gravity filter: follow the device's manual.

Read: how to choose a UV lamp for a pond, installing a UV lamp, and replacing the bulb or quartz of a UV. See also the UV-C replacement bulbs, the submersible UV devices, and the pond filters.

Experts since 1998. Doubt about sizing? Write to support@foudebassin.com or call +32 10 86 03 54.