This is why I am TOTALLY against any non-chlorine form of pool sanitation: I do not believe that any other method is proven to sanitize water against fecal contamination.

This is also why I prefer to run higher levels of chlorine in my pool than is "universally" recommended and follow the guidelines Ben established here. I try NOT to stay at the lower end of chlorine guidelines, just in case. I consider it "acceptable risk".

The water-borne diseases discussed are nasty but they aren't nearly as bad as the ones that, even through the early 20th century in America and Canada, were a risk: Cholera, Typhoid, Typhus, Ameobic Dysintery --all deadly killers and STILL a risk in the 3rd world.

Notice further, that to kill Crypto, our recommended shock levels should do it in 16 hours (they show that for FC of 15--our CYA = 30 - 50 shock level).

Crypto is one of the hardest to kill. When purifying drinking water, you have to leave the water for several hours to ensure its death.