Green hair comes from copper in the water. The first thing to do is figure out how the copper got in the water in the first place, as fill water almost never has any copper in it.
Copper comes from some kinds of algaecide, ionizers, "mineral" systems, and very low PH plus a gas heater.
Using sequestrant can help prevent copper in the water from turning hair green. But it is better long term to get rid of the copper, which may require water replacement.