What Did They Use Before Chlorine To Sanitize Pools?

[phishfood]

You know, like back in the 1400's-1700's or whenever was before the figured out to use chlorine?

[chem geek]

Before chlorine was prepared and studied in the late 1700's, its use against putrefaction, infection and contagion in the 1800's, and its use in public water supplies starting around 1890 (and in the U.S. widespread by 1918), water supplies varied in quality. This is why certain water-borne illnesses were prevalent, such as cholera. There were natural springs of hot water that were used and some of these had high enough mineral content (including sulfur) that they did not carry pathogenic bacteria (that didn't mean they were disinfected, but that the type of bacteria in the water was not pathogenic and that bacteria from fecal matter would not grow in such water). So many people died from so many different diseases in those days that worrying about catching something from swimming or bathing was pretty low on the list -- plus the germ theory of disease didn't exist yet.

Also keep in mind that outdoor bodies of moving water are constantly replenishing the water whereas in a pool or spa the volume of water is far lower and without disinfection and oxidation you are essentially soaking or swimming in your own sweat and urine (and those of others who also soak/swim in that water). Nevertheless, even in public waters that are considered to be in good shape, the risk for gastrointestinal illness is roughly on the order of 1-3 ill swimmers per 1000 per season. The risk in chlorinated waters is virtually zero (except for chlorine-resistant pathogens such as Cryptosporidium parvum).

[phishfood]

Interesting!

Was just reading where in Germany the recommends levels of ph is lower than most of the rest of the world. Been looking for why they have a lower rec than other places but haven't found anything so far.

[chem geek]

The DIN 19643 standard used in Germany for commercial/public pools has a lower pH because they use a low Free Chlorine (FC) level of 0.3 to 0.6 ppm (0.2 to 0.5 ppm if ozone is used), though this is without any CYA. They also use flocculants (iron or aluminum) that require a lower pH.