I've seen where people describe an unusual situation where the water turns green for a short period of time after adding chlorine then clears back up. This isn't happening to me but it peaked my interest and I never saw a definate conclusion on what caused it. If I have to I'll dig up the threads. What caused that reaction?
I know copper will turn the water green and also saw where the green color could have been an illusion by adding chlorine to water with sodium bromide (which is yellowish brown against a blue background creating a green color).