One can prevent blond hair from turning green after swimming in the pool by either wetting the hair, using a leave-in conditioner prior to swimming or getting a seal coat on hair at a salon. A person can wear a swimming cap to lessen the chance of blond hair turning green. It also helps to wash the hair as soon as possible after getting out of the pool.
Although people may think that it is the chlorine in pools that causes blond hair to turn green, the real cause for this happening is the oxidation of metals like copper and manganese in pool water. These oxidized metals bond or attach to hair strands and turn the hair green.
Because this hair problem is due to metals in the pool, another option to prevent this is to remove the metals from pool water or to not use algaecide products that are copper-based.
One method to fix green hair is to use a shampoo that contains a chelating agent like erythorbic acid. Another way is to wash the hair with a shampoo that contains either vitamin A or vitamin B, which are antioxidants. A simple home remedy is to apply tomato juice to the hair, leave it on for at least 10 minutes, shampoo it out and use a conditioner as the final step.