I was wondering in the days of ancient Rome, how did they keep their public baths (and city fountains for that matter) clean? Modern hot tubs, pools and fountains need chlorine or other products to keep algae/bacteria/scum in check. What was the Roman secret?
i’m not totally sure if this will answer your question(s), but reading this site
http://www.pbs.org/wgbh/nova/lostempires/roman/
explains the process in great detail
Remember, also, that your standard of cleanliness is probably higher than the Romans’ were.
Note that modern pools, etc. are filled, and then the water just sits there, available for algae/bacteria/scum to start growing.
The Roman system was largely continuously flowing water. Fresh water flowed into a pool on one side; used water overflowed out on the other side. Generally, algae/bacteria/scum grow best in stagnant water. So the Roman secret was just keeping the water running. (And they didn’t really have much choice about that. It isn’t like you can turn off a spring that’s the source of your water.)
We often think of the Romans as the most advanced of all ancient civilizations. While the Romans certainly did a lot of great stuff, their urban planning was wuite poor and the populace suffered as a result. Average life span for the Romans has been estimated at 41 years, less than for the Greeks, the Egyptians, and the medeival Europeans. Some part of this was likely due to the bad conditions in cities, which were often dangerous and unsanitary. And it certainly would not surprise me to learn that the baths were cesspools of bad sanitation.