irritating vapor coming off the pool

[coughinginthepool]

We are having a mojor problem with an irritating vapor coming off of our pool. The pool place has checked the water several times. First the chlorine was high, it has been adjusted. Then the minerals were off, they have been altered. Supposedly the water is perfect, but we are all still coughing. Anytime the water is stirred up with kids jumping in or splashing, everyone in the vicinity is coughing. We have also noticed a brown film in the valves where the water enters the pool. The pool people are no help. They suggested airing out the pool by leaving the cover off. We have kept it completely uncovered with no change in our problem. They are now saying the only solution is the drain the pool and start over. I don't trust this advice without knowing what the cause of the problem is. This is our 9th year with the pool and we have never had this problem before. Anyone had a problem like this?

Thanks,
Coughinginthepool

[chem geek]

What kind of chlorine is used to chlorinate this pool? Trichlor pucks/tabs? Cal-Hypo? Chlorinating liquid or bleach? Saltwater chlorine generator system?

Do you know the water chemistry parameters, preferably using your own good test kit such as the Taylor K-2006 or the TF-100? Specifically, do you know the Free Chlorine (FC), Combined Chlorine (CC), pH, Total Alkalinity (TA), Calcium Hardness (CH) and Cyanuric Acid (CYA) levels?

Is the pool indoors or outdoors? Is it exposed to sunlight? You mentioned a pool cover -- what kind of cover -- automatic opaque safety cover or bubble-type on a reel?

What is the size of the pool in gallons and how many people regularly use the pool and for how long (i.e. what is the bather load)?