Q: My water garden has turned green. Will a UV light help my pond?
Al – Mount Holly, NJ
A: Ultraviolet bulbs can work wonders in an algae-filled pond, particularly one in full sunlight. As the green water passes by the light, concentrated UV rays damage the tiny plants, ultimately killing them.
UV clarifiers work well and can certainly help your pond, but they shouldn’t be your primary method of algae control. Before investing in a UV unit, check your mechanical and biological filtration first.
Did you perform a thorough spring cleanout of your pond? Is your filter overloaded with debris? Do you need to wash out or replace your filer pads? Is the system sized appropriately for your pond? You may need to make some filtration upgrades. The Pond Guy® AllClear™ Pressurized UV Filter adds mechanical and biological filtration as well as a UV clarifier, giving you three types of filtration in one unit.
In addition to checking your mechanical filtration system, you should also make sure you’re following a regular maintenance routine by adding Nature’s Defense® and Muck Defense® to your pond. A healthy population of beneficial bacteria—your biological filtration—will keep the nutrient load in check, which will starve the algae out of your pond.
If your mechanical and biological filtration are taken care of and your water is still too green to enjoy your koi and goldfish, consider a UV light. Here are some tricks for choosing the right one:
- Wattage: The first trick to getting the best results is to pick a UV bulb that has a high enough wattage for your pond’s volume. All UV clarifiers are rated based on pond size. The larger the wattage, the larger the pond size the UV clarifier can handle.
- Flow Rate: The second trick is to pump the water past the bulb at just the right flow rate. Pushing water past the UV light too fast can render it ineffective, while pushing the water too slow can cause the UV clarifier to act like a sterilizer, killing not only algae but your beneficial bacteria as well. A great rule of thumb is to push the water approximately half of what the UV is rated per hour. For example, The Pond Guy® 9-watt PowerUV™ Ultraviolet Clarifier is rated for ponds up to 1,200 gallons, so a 600 GPH pump would be ideal.
Another point to consider: Do you want an above-water UV clarifier, like the PowerUV™, or a submerged one? If you’re looking for a below-water model, check out the Pondmaster® Submersible UV Clarifier. It includes a Halo Ring that lights up to show you the unit is working.
Pond Talk: What kind of luck have you had luck using an ultraviolet clarifier?
Filed under: Algae Control, Pea-Green Algae, Season-Long Control, UV Filter, Water Gardens & Features, Water Quality Issues Tagged: | biological filtration, mechanical filtration, poweruv, UV Clarifier, UV Filter, UV Filtration