New Max 10Ppm Chlorine Standard In Pools?

[researcher_in_canada]

I'm a researcher in Canada, looking for some research evidence to find out why most health authorities accept a maximum of 10ppm chlorine before ordering pool closure. Can someone point me in the right direction?

Thanks for your help.

[2n3055]

I'm a researcher in Canada, looking for some research evidence to find out why most health authorities accept a maximum of 10ppm chlorine before ordering pool closure. Can someone point me in the right direction?

Thanks for your help.

Email me.

[chem geek]

It is mostly because when Cyanuric Acid (CYA) is present in the water, the active chlorine (hypochorous acid) concentration is much, much lower so 10 ppm FC without CYA is very high but with 50 ppm CYA in the water it is equivalent to 0.2 ppm FC with no CYA. This is known science since at least 1974. You can read more about this in the "Chlorine/CYA Relationship" section in the Certified Pool Operator (CPO) training -- What is not taught post.