What is the difference between sanitation and oxidation?
Sanitation is the killing of viruses, bacteria, and algae on contact, while oxidation is the elimination of non-living organic contaminants.
Chlorine (Cl) is an excellent sanitizer and is meant to provide a residual in the water. Some problems, however, can be encountered when it is used alone to eliminate non-living organic contaminants. For instance, when chlorine encounters a non-living organic compound, it becomes incorporated into the compound and it cannot be broken down any further. This is called combined chlorine.
The combining of chlorine with contaminants in the water limits its ability to work as it is designed, thus it becomes less of a functional sanitizer, making it difficult to keep a residual of ‘good’ chlorine in the water. These (combined) chlorinated organic compounds also form waterline rings, clog filters, and result in the formation of soft scale.
Further, chlorinated compounds that are formed from sweat and urine (chloramines) are responsible for the obnoxious chlorine odour, as well as skin and eye irritation that may be experienced by bathers. As these chloramines form, more and more chlorine is needed to establish a sufficient free-chlorine residual in the water. This is known as shocking or super-chlorination.
Knowing the detrimental effect that non-living organic contaminants have on water, one must also realize the rate at which these contaminants are entering pools and hot tubs. For instance, the vast majority of adults would never reuse someone else’s bath water, yet many bathers skip the shower prior to entering a swimming pool or hot tub. A thorough shower with soap helps remove perspiration, body oils, cosmetics, and traces of urine and fecal matter on the body prior to swimming. Sending these contaminants down the shower drain goes a long way toward reducing the ‘yuck factor’ for everyone who shares the pool.
There is much more to consider, however. The pre-swim shower also helps to minimize the irritating smell of combined chlorine (chloramines). Many people identify this smell as if the facility is using too much chlorine, when in fact it is the inefficient combined chlorine previously discussed. In fact, a well-managed and balanced pool will not have any strong chemical odours.
While it is wishful thinking to imagine every single bather will adopt the pre-swim shower routine, the proactive use of enzyme maintenance products by swimming pool and hot tub professionals can significantly decrease potential water quality problems. Although it is hard to control what bathers add to the water, the consistent use of enzymes makes it easier to control what is removed, thus saving time, money, and the headaches of dealing with potential problems when they arise.
Chris Marcano is the director of training and education for Natural Chemistry Inc., a manufacturer of pool and hot tub specialty chemicals in Norwalk, Conn., and Campbellford, Ont. Marcano has 16 years’ experience in the industry and is a Certified Pool/Spa Operator® (CPO®) instructor, and a member of the education committee for the National Plasterers Council (NPC). He is also active on the Association of Pool & Spa Professionals’ (APSP’s) board of regents and is a local APSP chapter president. He can be reached via e-mail at cmarcano@naturalchemistry.com.
