The hygienic purity of water is essential for the success of biological pools. In some biological swimming pools for tourist use, it is confirmed monthly by regular analyses. Bio Piscinas, Lda. recommends that all tourist units with biological pool carry out this self-control of their own volition, despite the absence of a legal obligation to do so.

This lack of regulation also leaves doubts about the parameters to be analysed. That is why we recommend using the internationally practiced bacteriological parameters for this purpose, published for example by the WHO, which are Escherichia coli, Enterococcus fecalis and Pseudomonas aeruginosa.

Thanks to the good collaboration with our customers, we have a database with more than one hundred bacteriological analyzes of various biological pools in the country, most of them for tourist use, the largest serve hundreds of users per day.

As it is evident that this is non-publishable data, we cannot present results. But as an example we can talk about the limit values ​​for Enterococcus and Escherichia, bacteria of the gastrointestinal system used worldwide to detect fecal contamination in water. The international limits for biological pools for public use are 50 cfu/100 ml for Enterococcus and 100 cfu/100 ml for Escherichia (cfu = colony forming unit). These limits must be compared with the limit values ​​practiced in Portugal for river beaches, ie fresh water inland, which are 500 for Enterococcus and 1,500 for Escherichia. In other words, the quality of bathing water in a biological pool must be 10, respectively 15 times better than water on a river beach.

And as hundreds of analyses prove, the bathing water of biological swimming pools for tourist use manages to respect these limit values. That is, the water in the biological pool, in comparison, must still be 10 or 15 times cleaner than the water quality on river beaches.