Why is Ultra Violet (UVC) filtration important?
Small single cell algae are the usual cause of green water in garden ponds. These algae make it difficult to see into the pond and if you have fish they will only be seen for brief glimpses as they approach the surface. Technically this algae can lower the kh value, interferes with the nitrate/nitrite cycle in the biological filter, lower oxygen levels, and increasing “ph” levels. Ultra Violet is a safe technique used for obtaining clear water without affecting fish or plant life.
Ultra violet light clears water due to flocculation of the algae. Flocculation is the process of making very small algae cells expand and form clumps. These clumps or large particles are then big enough to be trapped by the mechanical medium in the filter. Sunlight and fish stock are the main factors in the promotion of algae's, and for such reasons the selected size of a UV unit should take such environmental aspects into account.
UV's also safely and effectively eliminates pathogens and bacteria
Rule of thumb for calculating UV requirement:
Ponds without fish stock should have 1 watt of UVC power per 1000 litres of water
Ponds with fish (no Koi) should have 2 watts of UVC power per 1000 litres of water
Ponds with Koi should have 3 watts of UVC power per 1000 litres of water
The flow rate of water through a UV must be kept within strict margins in order that the UV light has sufficient time to act upon the algae. Several of our UV units have means of adjusting water flow as well as automatic and continuous lamp cleaning to ensure the full strength of the UV light reaches the water.