Blondes, whether peroxide or another hair bleaching method, or just naturals, are susceptible to the green monster after a dip in the pool. Most of the time the most severe cases are peroxide blondes. Natural Blondes can suffer the same dilemma, more especially if their hair is dry or damaged.

The culprit is not the chlorine, as I’ve seen in many articles. It is dissolved and oxidized metals in the pool water. The problem can be assisted by extremely high chlorine, greater than 8.0 milligrams per liter (mg/l) or parts per million (ppm). But that is considerably higher than is recommended for a pool.

The major culprit is of the metals group, copper. Generally the quantity would need to be greater than 0.5 mg/l. Smaller quantities have created the same phenomenon when compounded with quantities of iron or manganese that has not totally oxidized. The partially oxidized iron and manganese will take on the stronger color characteristics of the copper like a prism does. A prism will reflect the colors around it stronger than the infinite rainbow it may exhibit in a white room with just the sun shining on it.

I read an article on a web site where someone said the problem was not the algaecide that the pool owner used. That statement was probably incorrect. The most widely used pool algaecide due to its effectiveness is a copper product. Used according to the Manufacturer’s label, one might add as much as or more than 1.0 mg/l of copper to their pool. The maintenance dosage is quite often kept at or around 0.5 mg/l. The main reason that the copper reacts quickly or worse in one pool more than another, in which both were treated equally, is due to the rest of the chemistry of the pool. With a low pH, alkalinity, calcium and total dissolved solids, the copper is more apt to stay in solution and do what it was put in there for, to reduce algae. On the other hand, with a high pH, and possibly other parameters high, the copper may stay in solution, but it has the tendency to form a scale or attach to other solids.

Hair, any hair, is susceptible to have metals form a scale on it. The green is just not as noticeable on other colors like it is on a Blonde. Hair is just a preferred surface, as it is porous and often the oils in the hair have a high pH, increasing the oxidation process. Iron and manganese follow suit in this simplified explanation of what is actually called the "Saturation point" for metals. Iron is normally noticed in pool water, and is generally treated to be removed, although small quantities might go unnoticed. Pool owners; on the other hand, do not often test for manganese. Most often it is diagnosed as just some form of metal. Varied water quality parameters will produce varied saturation points for these metals whether combined or if just one metal is present.

Pool owners are typically more concerned with algae and are not aware of the rest. Larger commercial pool owners often create the perfect opportunity inadvertently trying to make their water less corrosive by adjusting the water parameters to the high end of the acceptable pool chemistry settings scale. Often they are trying to stop copper corrosion in their piping system with these adjustments and just happened to use an algaecide with copper in it. Under these conditions, they should use one of a half a dozen other algaecides available for pools that are copper free, more especially if their water is corrosive and they must stop the corrosion as well as the kill the algae. Copper algaecide should definitely not be used in spas because, one; it produces foam, and two; the warm water will most definitely cause the copper to oxidize and stain the spa itself, much less hair and skin.

Removal of excess metals from the pool with a reputable metal chelating agent is suggested. Most are just called "metal out". They compound the metals to a particle size large enough that the filter will then remove them. Don’t use a sequestering agent for this purpose, as they just cosmetically cover up the problem and do not remove it as a general rule. They also are usually a form of phosphate or phosphorus or have some in it. Phosphates or phosphorus are on the top of food chain for algae and bacteria. That is why there are phosphorus/phosphate removers for pools.