UV or Ultraviolet light has been utilized in many industries. It is used for sterilizing instruments in the medical field as well as for sterilizing drinking water. It has also been utilized for aquariums and ponds for quite some time with regard to algae control. Basically there are four main components of the ultraviolet sterilizer: a germicidal lamp, a quartz sleeve to protect the lamp from the water, a ballast to supply the correct electrical requirements for the lamp, and the housing which holds the many other parts and the water flows through it.
There are plenty of misconceptions concerning the use of UV in water gardens. One problem is that you will sterilize your pond and kill all of the valuable bacteria. This really is not possible. Not all of the water will go through the UV in one circulation and there is always going to be beneficial bacteria within your biological filter and on everything in the pond, such as the liner. What the UV will do, when effectively sort of for your pond and flow rate, is decrease some bacteria, including harmful bacteria, as well as microscopic organisms that may be harmful to your fish. It will also destroy the DNA in single cell algae cells therefore getting rid of it very effectively. This will supply clear water when the turbidity is due to suspended algae. UV provides 100% success for achieving clear water from single cell algae in a pond.
Whilst Ultra violet will give you crystal clear water it does not filter the pond water. One concern of using UV in a pond is that some people will look at their perfectly clear pond and believe that the water quality has to be good for the fish. You may have clear water and still have water that could be harmful to the fish. Always have excellent biological filtration combined with the UV in your pond. You’ll need the biological filter to break down the ammonia given off by the fish and also to reduce dead organics including the dead algae that is wiped out by the UV. If you don’t have enough biological filtration then you may notice one algae problem cease to exist (green water) and another one (filamentous algae) replace it.
When searching for a UV you may find a number of confusing statements. Some companies don’t even call their UVs sterilizers. They call them clarifiers. Company x claims that their 25 watt UV is for ponds up to 1200 gallons and company y says that their 25 watt UV is for ponds up to 2300 gallons. What’s the deal? There are actually two reasons for the discrepancy. When a UV is sized as a clarifier it may not provide crystal clear water and a large number of plants are required to assist with the clarity. If a UV is sized for sterilization then you can have crystal clear water even without plants in the pond, although the plants will certainly make for a healthier pond. Also, there are differences in the efficiency of the UV light from one brand to the next. 25 Watts from one company may not be as efficient as a 25 watt from another company.
Adding a UV to your pond can provide some real benefits but get the facts before making your purchase and be sure to include adequate biological filtration as well.