Thanks for the responses.
First of all, I use municipal water and have been for the last eight years. Obviously something could have changed with the water this year. I only used the flocculant twice as a result of the pool being cloudy. Recently using Chlorine tablets, I did not see this problem. I hold the chorine content to between 3 and 6 ppm. The only metal in content with the pool water (vinyl lined) would be the ladder and possible pump parts (all pvc plumbed). What type of metal typically reacts with chlorine?

MJ