Great reply pooldoc! I will read through and digest now.

I did forget one big item....sorry bout this.

My daughter used to come out of the shower sneezing like crazy after every shower. I never knew what it was....we assumed different soaps, shampoos, etc were the problem. But, she hasnt had this problem since we moved into the new house. The sneezing, etc stopped completely. I assumed it was just a change in soaps, etc. But, as I think about it, on this new house we installed a whole house water softener with a charcoal bed in it. That probably removes alot of the chlorine and who knows what else? Maybe there is something else i not chlorine in the water that is irritating? I dunno!

As for the low chlorine pools, the one I am sure of is my parents. They added an ozone unit (Delozone Eclipse 2) and while they are away in summer (snowbirds) I watch their pool and keep the chlorine as low as possible. I dont know to what FC as I never test it (my father does the rest of the year though), but I keep it right on the edge of algae (as in a couple of times during the summer with the hot pool water the FC apparently drops low enough that Ill see a small amount of algae on one section of the pool wall....its the same section every time). If my daughter swims in this pool when its in this state....no reaction. When my father used to keep the pool as the Pinchapenny recommended (i.e. 3-5 ppm chlorine) shed get the reaction like crazy.

So, anecdotal info...yes, but there is something going on with various chemistries that causes her a problem. Maybe its not chlorine but some other siuation that occurs when chlorine is above a certain level.