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Copper, when used properly in a swimming pool, can aid in the prevention of algae growth in the hottest months of the summer. However, if you do not know how to control it, the metals can break out of suspension into the water and cause metal staining on your pool bottom, sides, steps, skimmer basket, etc. It may also cause the water to turn a yellowish brown color but still perfectly clear enough to see to the bottom.
The copper level in the pool may also turn blonde hair green. This is due to the harsh alkaline level. If it happens, you need to shampoo with a more acidic "swimmers" shampoo. I believe Aveda may sell one that gets the green out.