Safe swimming with elevated chlorine

[waterbear]

If I let the number of negative reputations that I've gotten upset me I would not be an active member of this forum. I just got one for a posting in a thread about filter sand but I was the only one that was able to provide any advice that actually helped the starter of the thread even though my advice went againts the beliefs of some of the Mods and Ben. Everyone else that posted in the thread just just kept asking, 'why do you think you have this problem?' It's just a way for people to express their opinions...not a big deal! Getting back to the topic of this thread. There is a lot of conflicting info about chlorine levels. Until very recently 1 ppm was considered enough. Now in many areas 2 ppm is the minimun for a commercial pool becase of new research on kill times for some water born illnesses. As far as maximum levels, that depends on the local health departments. I believe Texas has an upper limit of 8 ppm and if I am not mistaken Hawaii is 5 ppm. None of these take into account the CYA levels which are ususally permissable up to 100 ppm and most recommend a level of about 40 for outdoor pools from what I have seen. One commen requirement is an ORP reading of 650 mv if an ORP sensor is used. It is a known fact that higher FC levels are necessary at higher CYA levels to obtain an ORP reading of 650 MV....much in line with Ben's 'best guess' CYA chart. IF htere is no CYA in a pool then the 650mv ORP reading is obtainable with 1-3 ppm FC. As soon as CYA is introduced into the water a higher FC level is needed to obtain the 650 mv reading.