I had the green hair thing happen to me before. On my honeymoon - long blonde ponytail. My new hubby said, as we were walking down the beach, "Your hair is green!" I didn't believe him at first, but sure enough, it was. I assumed that it was from the chlorine in the hotel pool -- now I know better. It was from copper in the pool. Spent the next day at a beauty shop having them put some bright red stuff on my hair. Whatever it was, it worked. Back to blonde. (Of course, I always tease my hubby that it was a sign that I shouldn't have married him! )