5 ppm is *NOT* too high to swim; that's bogus stuff that traces back to standards that were established in the '60's, on a purely 'pulled that one out of the air' basis. During the *same* time when "above 3 ppm" was set as "too high to swim", there was NO upper limit on chlorine in drinking water. Some utilities routinely shipped drinking water at 10+ ppm, so there would still be chlorine in the water when it reached the end of their old and corroded water lines!
However, if you still have no CYA, that chlorine will drop by over 1/2 in an hour of full sun!
Read the Best Guess page, linked in my signature, to get a better understanding of this.
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