Hi Madlou, Just a thought. Chlorine is added to the water at many water treatment plants that so many of us get our water from every day; if not at home at the places we visit.
I have spent a lot of time in pools (including at the Y) and never noticed any impact on my MS. Believe me, I invouluntarily drank a lot of pool water when my former employer brought in a former Navy Seal to teach us how to survive in the water in an emergency (I'm still convinced he was actually trying to teach me how to drown
especially after he caught me cheating. Hey, I was young and stupid. Don't try to fool a Navy Seal in the water was the lesson I learned that day. After he caught us cheating, he decided to teach us how to use our head for a bobber to float. I think I proved I was not an airhead that day considering all the water I drank, but eventually I learned how to do it.
Despite all the punishment I was able to see that swimming was a great form of excercise that didn't put pressure on, or injure my joints, although I have heard that "extreme" swimmers have their activity related injuries also (i.e. rotator cuff), I still think it is a great alternative aerobic activity to running or walking as may be the case with an MS'r, and it carries much less risk of injury overall. Running is not an option for me anymore. I can do it, but that's when people can notice my wobbly gait.
Finally, I would agree with Uppity and be more concerned about
the water temp. I have a great neuro with great nurses so I would call them for advice on the chlorine vs. immune system question.
Good Luck and happy swimming.