Ultraviolet (UV)

UV Sterilization is the safest method of preventing and eliminating problems in an aquarium or pond. UV will not kill a parasite on the fish, but parasites go through a free-floating stage, at which point they are eliminated. Additionally, corals and fish can and do carry bacteria that can infect and spread throughout the tank, killing other inhabitants.

The initial thinking on reef tanks was to avoid UV, to keep plankton alive. However, with the skimmers and pumps used in ponds the plankton population in the water column is virtually non-existent. You can use a UV continuously (recommended) or just keep one at the ready, in the event of an outbreak.

Points to ponder about UV Sterilization

Most effective when run 24/7.
Most effective if the water is clear.
Most effective if the bulb is new, or replaced regularly (at least every 6-8 months).
Most effective if the UV light penetrates less than one inch of water.
Effectiveness can be hindered if the water passes too fast past the bulb.
Most effective if the exposure time of the water to the UV light is longer than one second.
The effectiveness of UV light can be hindered if there is a light blockage, i.e. a salt-encrusted bulb.
It can help to prevent future water-borne pathogen reoccurrences, once the initial problem has been completely eradicated from the pond.
UV light not only kills unwanted organisms but beneficial ones as well.
Should never be run when treating with any drugs or medications.
UV can also alter the structure of some dissolved chemical compounds.
UV light can be damaging to the human eye, so DO NOT look into the bulb.
Always unplug the unit when working on it to prevent possible shock if it breaks or gets wet.