The latest pool and spa maintenance alternatives
Concerns about the safety of chlorine has lead to a number alternative options for pools and spas giving consumers more choice. Traditional pool and spa water maintenance has involved using mainly chlorine in swimming pools and either chlorine or bromine in spa water. In pools chlorine acts as both a sanitiser and also as an oxidiser of organic waste. Scientific studies have shown that there are considerable health risks associated with the use of these chemicals mainly because of the disinfection by-products that are produced as the chlorine and bromine attempt to oxidise human body substances, sunscreens and organic matter (Burns & Linden, 1997; Zwiener et al., 2006). Because of these health risks new healthier options are emerging in the marketplace for treating both pool and spa water giving consumers more choice.
Biguanide is a chemical sanitising alternative to chlorine. It is not as susceptible to UV rays as is chlorine and it also does not degrade in high temperatures or with pH changes. Because biguanide is a sanitiser only, occasionally a shock treatment is required to oxidise organic matter but it is not compatible with traditional non-chlorine shock products and hydrogen peroxide (see below) is recommended.
Pros: stable, silky water feel
Cons: more expensive than chlorine, can gum up filters
Ionisers make use of the disinfecting properties of silver and copper. An ion-generating device is installed the pool or spa’s circulation system and releases silver and copper ions through electrolysis into the water. Although ionisers are effective water sanitisers, they do not oxidise organic matter so it is still necessary to shock treat or super chlorinate the water regularly. The silver and copper ions can also sometimes stain pool and spa surfaces and discolour the water. Water balance needs to be maintained using traditional pH adjusters.
Pros: much less chlorine/bromine needed in the pool or spa
Cons: can be expensive to set up, possible staining of surfaces
Mineral sticks and floating ionisers
Mineral sticks are floating ionisers are other methods of using mineral ions such as silver and copper to sanitise pool and spa water. They differ from ionisers in that they are tubes that are inserted inside existing spa or pool filters although their mechanism of sanitisation is the same. As with ionisers, mineral sticks are not able to oxidise organic waste in the water and must be used with chlorine, bromine, non-chlorine shock or hydrogen peroxide (see below).
Pros: much less chlorine/bromine required
Cons: can be expensive
Ultraviolet radiation (UV)
UV pool water sanitisation devices use UV rays to kill micro-organisms in the water of a pool or spa. The system is installed in the filtration system and after the water is filtered it passes through the UV chamber. As with ionisers this system takes care of the sanitising of the water but an oxidiser still needs to be used.
Pros: much less chlorine or bromine needs to be used
Cons: may have a high initial cost to set up
Ozone is a gas that is formed by UV rays separating an oxygen molecule (O2) causing the separated O molecules to attach to other O2 molecules resulting in O3 being formed. The O3 (ozone) is a powerful sanitiser and oxidiser before it is rapidly broken down into oxygen again (O2). Ozone is actually a highly toxic gas that must be removed from the pool or spa before use. Because there is no residual ozone remaining in the water additional small amounts of sanitisers and oxidisers must be used.
Pros: powerful sanitising and oxidising agent, use much less chlorine/bromine
Cons: requires the use of some sanitising chlorine/bromine
So far all the alternatives discussed (apart from ozone) are water sanitisers and therefore still require an oxidiser, which has traditionally been either chlorine or a non-chlorine shock. So although the overall amount of chlorine used is reduced, a small amount is still sometimes required. Using chlorine as an oxidiser still leaves users exposed to the health risks associated with disinfection by-products. The following methods offer alternative means of oxidation of organic matter.
Hydrogen peroxide is a powerful oxidiser. It can be used to dramatically reduce the need for chlorine or bromine in a swimming pool or spa as the chlorine is only required to sanitise the water. Combined with sanitising alternatives such as UV lights, ionisers and biguanide the need for chlorine can be eliminated altogether.
Pros: replaces the need for chlorine or non-chlorine shock oxidisers
Cons: large doses required, quickly disintegrates, can be expensive
Mimicking nature: non-sanitising approach
So far all the alternatives to chlorine and bromine discussed require a sanitising component that completely remove micro-organisms from the water paired with an oxidiser that breaks down organic waste. The following two alternatives represent a break away from the sanitising approach in that they do not attempt to remove micro-organisms but rather attempt to mimic a natural balanced body of water in which pathogenic bacteria cannot proliferate due to populations of beneficial, naturally occurring micro-organisms.
Natural pools are an exciting new alternative to traditional pools. Instead of using any chemicals they rely on plants, mechanical filtration and naturally occurring micro-organisms to balance and purify the pool water. Usually they are comprised to two parts; one is the swimming area and the other is a ‘regeneration zone’ where aquatic plants and a bio-filtration system refresh the water. The water is circulated through the two areas by a low power pump.
Pros: completely natural, chemical-free water, low on-going costs
Cons: water murky or green in appearance
Enzyme based water purification systems work in a similar way to natural pools in that they promote a natural aquatic ecosystem in a pool or spa. Enzyme products typically contain surfactants to break down organic waste to a smaller size, a blend of natural enzymes and coenzymes that rapidly start natural oxidation and the self-purification of the water and sometimes a nutrient blend to support beneficial micro-organisms. Enzyme systems are most effective in spas and swim spas and can be used without any other chemicals. They can be used in swimming pools effectively as an oxidiser and water softener although a small amount of chlorine is still required (0.5 ppm).
Pros: cheap, non-toxic, easy to use (minimal testing)
Cons: still require a small amount of sanitising chlorine when used in a pool due to open nature of a swimming pool (that is no lid)
Clear Choice stock a range of enzyme based spa and swimming pool treatment options. Click here for more information about these products.
Although there a number of alternatives to chlorine and bromine for treating pool and spa water, enzymes and natural pools both represent a break away from traditional methods of pool and spa water maintenance and offer real alternatives to toxic chemicals for keeping pool and spa water healthy.
Anscombe, D., I. (n.d.). Biguanide: a chlorine-free method. Pool and Spa Outdoor. Retrieved from http://www.poolspaoutdoor.com/pools/water-care/articles/biguanide-a-chlorine-free-method.aspx
Burns, M. J., & Linden, C. H. (1997). Another hot tub hazard : Toxicity secondary to bromine and hydrobromic acid exposure. CHEST Journal, 111(3), 816–819. doi:10.1378/chest.111.3.816
Fact Sheets. (n.d.). SPASA Swimming Pool and Spa Alliance. Retrieved from http://www.spasa.org.au/for-consumers/fact-sheets.html
Hydrogen peroxide pools. (n.d.). SpectraLight Ultraviolet. Retrieved from http://www.spectralightuv.com/hydrogen-peroxide-pools.html
Mineral Purifiers/ Sanitisers. (n.d.). Pool Supply Unlimited. Retrieved from http://www.poolsupplyunlimited.com/products/MineralPurifiersandSanitizers/27
Paradise every single day. (n.d.). Aquaviva Natural Swimming Pool Australia: Swimming Pools without chemicals. Retrieved from http://mynaturalpool.com.au
The Best Pool Water Starts with UV Pool Systems . (n.d.). SpectraLight Ultraviolet. Retrieved from http://www.spectralightuv.com/how-uv-works.html
Zwiener, C., Richardson, S. D., De Marini, D. M., Grummt, T., Glauner, T., & Frimmel, F. H. (2006). Drowning in Disinfection Byproducts? Assessing Swimming Pool Water. Environmental Science & Technology, 41(2), 363–372. doi:10.1021/es062367v
Photo credit: pedro_cerqueira / Foter / Creative Commons Attribution 2.0 Generic (CC BY 2.0)