Once again, if its monitored and maintained properly, sure why not? Partial cycling when things that can't be filtered get too high (like TDS or CYA for an outdoor pool) but otherwise make sure sanitization is happening properly, pH and other metrics stay balanced, and good filtering is happening, I don't see a problem.
> more than once a year because of various contamination
Sounds like that falls into the "unlucky" category.
If its that you don't like thinking about tons of other bodies have touched that water you're swimming in, remember that dinosaurs pooped in much of the water you're drinking today.
> Partial cycling when things that can't be filtered get too high (like TDS or CYA for an outdoor pool)
Partial cycling in a high traffic environment seems like it is clearly ending up being a lot of water when every number I can find suggests it is generally expected to add up to several times the total pool volume per year.
> Sounds like that falls into the "unlucky" category.
To me it feels like it falls in the "expected" category somewhere that is dealing with hundreds of swimmers including small children every day.
Keeping in mind this was across dozens of pools - he swam competitively, not a one-off or rare occurrence in a pool or two.