UV equipment is especially good at pond treatment. According to UV expert Ann Wysocki, writing in the Dec. 2004 issue of Water Technology Magazine:
Disinfecting a pond utilizing UV technology effectively reduces free-floating algae, bacteria, and other microscopic planktonic organisms.
The overall advantage of the ultraviolet method is its effectiveness — all microorganisms are susceptible to ultraviolet disinfection; it's economical, as hundreds of gallons can be purified for each penny of operation and the method is safe without the danger of overdosing and no dangerous chemicals are needed. This process happen automatically and it continuously disinfects without special attention or measurement and is easy to install and maintain.
(whole house & well units)