As frequent reports about recreational water illness and bacteria outbreaks mount, many commercial pool operators are choosing UV sanitation in order to comply with water quality testing parameters and state mandates. Some residential pool owners also are turning to UV for the ease of use, the significant health advantages, chemical reduction and the desire to go green.

But not all UV is the same. This article looks at what UV offers and the distinctions between low- and medium-pressure units.

What is UV?

Ultraviolet radiation is an invisible light emitted from the sun. This natural phenomenon is reproduced inside reactors via powerful lamps using the latest technologies and emitting germicidal UV-C radiation. UV-Cs penetrate the heart of any organism’s DNA, disrupting its metabolism through total destruction. All germs are thus deactivated and can no longer reproduce.

In a UV sanitation system, the pool water circulates directly under the exposure of the UV lamp, allowing the radiation to eliminate protozoans and bacteria. UV has gained traction in part because of its ability to eliminate chlorine-resistant microorganisms such as giardia, toxoplasma and cryptosporidium, which are common causes of multiple pool closures nationwide. UV also is popular because of its ability to remove chloramines.

Low- vs.medium-pressure

Basically there are two different types of UV lamps: a low-pressure lamp, which emits UV rays only at 254 nm, and a medium-pressure lamp, which emits UV rays between 200-600 nm.

Generally, low-pressure UV lamps may be better suited for residential applications, while medium-pressure models typically are designed for large commercial installations. This distinction can be chalked up to cost, flow requirements and the ability to destroy trichloramines.

Due to their large spectral (200-600 nm), medium-pressure lamps more effectively reduce the health problems caused by nitrogen trichloride, which again have been linked to numerous pool closures.