ULTRA VIOLET LIGHT:

A frequency of light that is invisible to humans that is emitted by the sun and special lamps. It can cause chemical reactions and causes many different substances to glow (used in black lights).

 

ULTRA VIOLET LIGHT TREATMENT: 

Harnessing special UV Light radiation to destroy water contaminants. It is also used to create ozone molecules for the same outcome.

 

UNDERDRAIN: 

The lower portion of the collection system in a swimming pool filter - used to direct previously filtered water back into the swimming pool. During backwash treatments it pushes the water in reverse.