Could ultraviolet sterilizers possibly be the only type of filtration that is needed for a pond?
Uh, no. Ultraviolet Sterilizers could possibly be the most misunderstood type of filtration for a pond. Many pond owners hook up UV sterilizers for the wrong reasons or when there is no need for them to begin with.
The pond and aquarium industry is heavily dependent upon filtration to be able to continue its growth and success. Without filtered water who would want to keep a backyard pond, or have an aquarium in their home? When it comes to filtration the pond and aquarium industry has very smartly begun to utilize equipment and technology that has been developed for water purification plants and also technology from the medical industry. As a matter of fact many of our efforts as pond owners could more likely be described as water purification efforts rather than just filtration.
This is where we get our use of Ultraviolet Sterilization from. UV sterilization is used regularly in the field of medicine, and is a staple component in water purification plants that produce our drinking water.
Ultraviolet sterilizers come with some big claims like algae control and disease control; not totally unfounded claims, but the user of the Ultraviolet lights may not realize that to achieve those results the UV Sterilizer needs to be hooked up for the specific purpose of what it is trying to achieve. In other words it is not a plug in and walk away type of system. This makes it important to know: what is an ultraviolet light? And how does an ultraviolet light work?
When applied to a pond or water garden the UV sterilizer is a very effective way to control green water. But the “algae control” buck stops there. When UV sterilizers are used to control ANY other type of algae beyond floating planktonic cellular algae (green water) it will fall very short of consumer’s expectations. Ultraviolet sterilizers do nothing for hair algae, slime algae, floating algae (pond scum); and it can even be argued that the UV treatment perpetuates the problem of green water and only serves to temporarily hide the actual problem of why water is turning green in the first place.
The UV does in fact control diseases such as free floating bacteria and some parasites, however to control bacteria for example; the UV sterilizer must be calibrated to allow a certain flow rate (gallons per hour) to pass through the light chamber to kill specific bacterium. For example to kill “bacteria A” the flow rate needs to be calibrated for 500 gallon per hour passing through the chamber, but for “bacteria B” the flow rate needs to be 200 gallons per hour passing through the treatment chamber, and for “bacteria X,Y, and Z” another flow rate all together. What works to control A does not control B or X, Y, Z. Whether bacteria, parasites, or algae; the flow rate determines the time of exposure that the subject has to the Ultraviolet light. Treating parasites with UV is somewhat effective, but not very and the same dilemma occurs. The exposure time it takes to kill Ich does nothing for Costia, and trying to treat Argulus is nearly impossible. For these reasons the Ultraviolet sterilizer is not typically even considered for disease control by most pond professionals, other than a “blanket” treatment and hope for the best.
Algae control is the same. If algae grows on the surface of rocks, liner, equipment, etc then a UV will do nothing for those algae, however if it is a floating algae and can pass through the chamber then the light will be effective. This free floating algae passes through the light unit, becomes exposed to the deadly UV light, and dies. The dead algae will drop into the pond, decay, create nutrients, and cause more algae to grow. This is not an effective solution to solving a problem, indeed it perpetuates it. The problem of green water needs to be addressed via filtration practices and most pond installations are chronically under filtered. A properly filtered and managed pond will result in clear water conditions. However; the argument remains that the Ultraviolet light is an effective quick fix to green water, but NOT a solution to the actual problem creating the green water.
So before making the investment into a UV lighting system which will run at least a few hundred dollars, typically more, take a good look at how your filter system is performing. Be sure to understand, how does an ultraviolet light work? Consult with a pond professional too, often times some very obvious problems are right out in the open but need to be pointed out by a trained and experienced eye. This could save you hundreds, even thousands of dollars.
And remember, Ultraviolet Sterilization is amazingly effective technology that has enriched our lives, but it may not actually be the best answer to what you are hoping to achieve in your water garden or koi pond.


Leave a Reply

Your email address will not be published. Required fields are marked *