Ultraviolet Disinfection (UV-C) for Hot Tubs

In-line UV disinfection is recognized as an effective and reliable method for deactivating pathogens in hot tub water, in addition to reducing bather exposure to dangerous byproducts.

Recent changes in regulations requiring supplemental water disinfection for public swimming pools and hot tubs have brought ultraviolet (UV-C) technology to the forefront of many discussions of improving water quality. Various halogens and sanitizers are used to treat waterborne pathogens in hot tub water, while many residential hot tub owners are also incorporating a supplemental disinfection system (SDS) into their hot tubs to assist in water sanitation.

For this reason, UV-C water treatment technology has seen increased popularity because it is environmentally friendly, easy to use, reduces chemical consumption, red-eyes, and damaged hair and skin, and improves water and air quality for hot tubs and their surrounding areas-especially indoor units.

Awareness increases in Canada for spa water

In the Canadian spa/hot tub market there has been increased awareness for UV-C technology as manufacturers are now including these systems on their hot tubs. Used in conjunction with other known oxidizers (e.g. bromine [Br] or chlorine [Cl]), UV-C reduces the amount of chemicals needed, thus allowing the oxidizer to be more effective in hot tub water, especially since the warm water has a propensity for more pathogens.

When properly sized for hot tubs, UV-C eradicates bacteria and viruses and does not add anything corrosive to the water, leaving it cleaner and clearer. Contrary to other sanitation devices, UV-C is best suited for use when people are using the hot tub; therefore, when the hot tub is in use, the UV-C should also be on. Further, UV-C is clean light and is not harmful in any way.

Today's UV lamp bulbs will last approximately two years (16,000 hours of constant use), which means maintenance is as simple as changing a light bulb. These high-output, low-pressure bulbs can be ordered online and are even stocked by most hot tub professionals. The cost of the bulb is less than the amount of money saved from using fewer chemicals in the water.

Standard protocol

In North America, the standard protocol for water quality maintenance (WQM) is premised on the assumption appropriate filtration and residual halogen disinfection will inactivate all pathogens. However, the following is known:

It can take chlorine up to 45 minutes to deactivate Giardia;
It can take 30 to 60 minutes to deactivate Norovirus; and
Cryptosporidium (Crypto) can linger in pool water for up to 10 days as it is highly resistant to chlorine.

Unfortunately, recreational water illnesses (RWIs) are dramatically increasing and as result, health officials have acknowledged a paradigm shift in the way swimming pool and hot tub water is treated. In-line UV disinfection is recognized as an effective and reliable method for deactivating pathogens in hot tub water, in addition to reducing bather exposure to dangerous byproducts.

Moving beyond the basics of hot tub water quality management will require revising the two-pillar approach to water treatment and adopting a supplemental disinfection method.

By Jeff Boynton from Pool & Spa Marketing. Jeff Boynton is the director of operations and sales for Delta Ultraviolet Solutions, a manufacturer of UV-C technology in Gardena, Ga. He is responsible for managing the company's existing customers as well as growing sales in North America. Boynton has worked in the swimming pool and spa industry, primarily in Europe, for more than 22 years. He can be reached via e-mail at jeffb@deltauv.com or for more information, visit www.deltauv.com.