I cannot tell you how many people purchase a home that has a pond with equipment they are not familiar with. One of these pieces of equipment is often a pond UV Light. Sometimes they don’t even realize they have it.
It might be found in the skimmer if you have a Savio skimmer or it could be in a little shed with other pump equipment. We see many Aqua Ultra Violet brand UVS. It could be found in an area outside the pond, in line with the pipe. It could also be part of the pressure filter.
This is an Aquascape pressure filter. The UV light is in the center.
What Does a UV Light in a Pond do?
Ultraviolet (UV) lights used in a pond eliminate the pea-soup colored water. They may also be referred to as a “Clarifier”. The pea-soup green water is really suspended or “microbial” algae.
How a UV Light in a Pond Works
A portion of the water runs through the chamber with the UV light. Exposure to the light kills the suspended algae! It also kills (or sterilizes) beneficial bacteria or anything else living in that water. (no, the fish cannot get in the UV light pipe).
Not every pond requires a UV light. When the ecosystem is in balance, there should not be suspended algae. If you are wondering if your pond ecosystem is balanced, read more about it by clicking HERE.
There are some ponds that are concrete and cannot have all the elements an ecosystem pond needs. Even an ecosystem pond may struggle with persistent green water.
The UV light is in this chamber.
If you are having a suspended algae problem, ask yourself these questions:
- ○ Am I putting in Beneficial Bacteria regularly every single week and giving it extra when it rains? Aquascape has a good bacteria for this called “Clear”.
- ○ Is there runoff from the yard? Runoff from from lawn fertilizers or weed killers kills beneficial bacteria in the pond and can lead to algae blooms. (not to mention that it can kill the fish!)
- ○ Am I over feeding the fish? Make sure you are only feeding them what they can eat in about 3 minutes. If there is a big suspended algae issue, cut back a feeding if you are feeding them more than one time a day.
- ○ Is the pond in sunshine all the time with no shade? Try adding water lilies for more shade in the pond and/or a sail shade to stop the sunshine from heating it up so much.
Here is a look at microbial algae.
UV lights are not all fun and games!
No shade to the UV people… but sometimes these UV lights are problematic. What am I talking about? Let me tell you –
1. The lights should not be touched with with bare hands. The oils on our skin cause the bulb to break much faster, so gloves must be work when handling it.
2. UV bulbs should not be left out over the winter. They should be brought inside. When they are left outside they almost always do not work the following year and must be replaced.
3. Even when they are brought in, they may need to be replaced yearly.
4. When they need to be replaced, even when you have the box and all the information, matching them up to the place to order them from is not as easy as you might think. I’ve done it many times and often I use the part number and yet, it comes up with something different.
5. UV lights can be expensive. Depending on the brand they could be $50, but I’ve seen some over $500!
6. Once you place the order it may take a long time to receive. Sometimes we get it right away, but other times it takes SO long! When I have a customer waiting with a green pond it can be very frustrating that we can’t’ get it sooner!
7. And the last and possibly most frustrating (maybe, #6 is REALLY frustrating…) is that it takes time to work. YES! It takes time for the water to cycle through the UV chamber.
What to do about a UV light and the pond?
Many ponds we service were built in such a way that they need a UV light. They may not have gravel, or the right type of gravel, to support beneficial bacteria. They may not have good places for aquatic plants to live. They might be solid concrete!
Oxygen and good circulation – Algae loves some good stagnant water to muck about in
Plants ( 40 to 6 percent surface coverage)
Sunlight – but not 100% of daylight hours! Some shade helps keep the water temperatures stable.
Filtration – did you know a stream or waterfall is part of the filtration? It is. A Biofall with bioballs and filter mats, a skimmer with basket or net and a filter pad, and/or pressure filter is also part of filtration. (of course plants are and I already listed them)
Structural Integrity. You might wonder how lack of structural integrity (read: it’s leaking) has anything to do with algae or the balanced ecosystem. If you are treating water with beneficial bacteria and the water is balanced with plants, fish and everything else, a leak can allow good water to escape and fresh, city water might need to be added often. This chlorine filled, no bacteria having water will throw off the ecosystem of the pond, causing…..ALGAE!
Building a pond - Include a UV light or not?
To UV or not to UV… that is the question.
If you are building a pond as an ecosystem pond with all the elements it needs to be healthy, you won’t need one.
If you are building a structure that holds water, has a bottom drain or is made of concrete, you might need one!
Already have a pond with a UV light?
If you have a pond with a UV light, that’s fine! Be proactive and figure out what bulb you need and have one on hand. Once you have the UV light they do fight suspended algae and do not require maintenance until they need to be replaced. Make sure that even if there is a UV light that you still try to offer all the elements a healthy pond needs!