Improved Swimming Conditions: Safer and More Pleasant Recreational Water

The risks of swimming pool water arise when the filtration technology and chlorine cannot effectively clean biological matter from recreational water, or when chlorine is used excessively.
The pores in conventional pool filters, such as sand and glass media filters, can be as much as 100 times bigger than dangerous micro-organisms found in pool water. Even under optimal operating conditions therefore, such filters cannot thoroughly contribute to the disinfection of pool water. This ineffectiveness is magnified by their low mechanical integrity over time. The granular structure of these filters gradually degrades (channelling), further reducing its capacity to clean particulates and micro-organisms from the water. Pools with granular filters typically rely on chlorine and chemical disinfectants from the outset, to compensate for the initial low-efficacy of the filtration media. As that media begins to degrade, the reliance on chemical agents increases. However, some dangerous micro-organisms, such as Cryptosporidium Parvum and Giardia are both chlorine-resistant and small enough to pass through some granular media filters, especially when their filtration velocity is high.
Crypto outbreaks are particularly concerning as just a small number of the germ is enough to make a swimmer sick. They are now twice as common in the US as they were in 2014, and are the second-leading cause of diarrhoeal disease and death in infants. According to research, as much as 84% of Americans are unaware that chlorine does not kill crypto instantly and 1 in 4 adults would still enter a swimming pool if they were experiencing symptoms of diarrhea.


Crystar® membrane filters have stable and small enough pore sizes to efficiently and consistently remove bacteria and protozoa from the water, representing and efficient mechanical barrier against micro-organisms. Crystar® HiFlo, for instance, has shown a retention efficiency of 99.996% against Cryptosporidium, without the use of flocculants. This vastly reduces the risk of the germ perpetuating in pool water and infecting swimmers.

Chlorine water disinfection, especially at high contents, brings additional drawbacks. Free chlorine reacts with nitrogen and carbon compounds from our bodies, forming aggressive compounds such as chloramines and trihalomethanes that are then re-introduced into the pool. These reactions occur mainly at the filtration media, where the reactants are in contact with the particulate and retained organic matter.

Outmoded granular filtration systems used in conjunction with chlorine is typically the cause of skin and eye irritation from pool water. This also directly contributes to respiratory issues such as asthma1. Trichloramines are by-products of pool water disinfection that are known to exacerbate asthma symptoms in swimmers who suffer with the disease or to develop asthma in healthy swimmers frequently exposed to the pool environment. There is data to suggest that swimming in chlorinated pool water has contributed to tens of thousands of cases of asthma in the developed world, although the causal link is still inconclusive.
Frequent backwashing of the filtration media is one of the primary methods recommended for the reduction of chloramine and trihalomethanes, alongside increased rates of pool water renewal.  Yet these measures lead to significantly higher water consumption.

In a nutshell: alternative filtration technologies have been established to vastly reduce the risk of micro-organisms outbreaks and chloramine and trihalomethanes generation. These systems use Crystar® FT, an advanced ceramic membrane that filters microscopic organisms from pool water with excellent levels of efficiency making it cleaner and safer, and generally more pleasant by reducing eye and skin irritation and chlorine odors. With Crystar FT membranes, you can enjoy your aquatic leisure activities to the fullest!

1 Eur Respir J 2002; 19; 790—793, DOI 10.1 1183/09031936.02.00308602, UK

Water Treatment Video

Play the video for a demonstration on how Crystar® FT ceramic membrane filters improve the water quality in swimming pools.


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