People often confuse UV clarifiers with UV sterilisers. These two filters are actually one and the same. The use of the terms “clarifier” or “steriliser” only refer to the extent of functioning. Therefore, much depends on how you want to use the device in your pond.
For instance, if your intention is to clear up the green hue in your pond, then a UV clarifier will serve your purposes. A UV clarifier is designed to expose the water to sufficient UV to destroy any free-floating algae. Usually, this type of filter is the preferred choice.
How a Steriliser Works
Alternatively, a UV steriliser takes pond purification a step further by controlling such pathogens as viruses, protozoa, and bacteria. As a result, a steriliser exposes a pond to more UV than a clarifier. This type of unit can be helpful if you want to prevent the spread of disease throughout the water. However, you need to keep in mind that a steriliser only kills organisms floating through the UV tub, therefore, it will not kill any infestations already on the fish.
Whether a device is described as a clarifier or steriliser depends on two factors:
- The wattage of the UV bulb
- The flow rate through the tubing
A Recommended Filter
As a result, UV filters that are usually called sterilisers are of a higher wattage than clarifiers. However, a 25W steriliser filter in a pond holding 3,785 litres would be considered a clarifier in a bigger pond holding four times that amount, so you also have to consider the pond’s size. In most cases, it is a good idea to get a top quality pond filter like the OaseFiltoclear, which features a pressurised pond filter with an integral ultraviolet clarifier. Pressure filters supply superior biomechanical filtration, eliminating toxic nitrite and ammonia along with particulate matter.
Pressure filters are outstanding filters to use in small to medium-sized ponds containing gold fish, koi fish, and other ornamental fish species. They can also be used in larger ponds with a skimmer filtration system already in place. Their ease of installation makes them a first choice for an existing or newly-built pond.
Other Factors to Consider
Other factors that impact the choice of filtration include the following:
- The number of fish in a pond
- The amount of sunlight a pond receives
- The manufacturer’s specifications
- The water temperature
With respect to flow rate, the speed at which water flows along the UV bulb determines whether the organisms will be destroyed (sterilised) or mutated, so reproduction cannot occur (clarified). Therefore, a higher-watt bulb can be termed as a clarifier if the flow rate is faster.
In most instances, if you are unsure, it is best to go with a pressurised filter that features a UV clarifier. This type of product normally will “clear up” any issues you may have with green water or pathogens.