Something sounds fishy to me. Did someone dump green dye in the diving pool. But then I remembered from high school chemistry that copper compounds are greenish. That’s probably going on – too much copper in the water looks OK until chlorine is added. Then you have a nice green compound.
“Copper is one of the few colored metals. Most metals are gray or silver. Gold, copper, caesium and osmium are the only four colored metals. Copper is green as copper(II) carbonate and copper(II) hydroxide. It turns green because it oxidises. After a time in the air, copper forms green copper carbonate at the surface, called verdigris. That is why the copper roof of a building looks green.”
So it looks simple but probably isn’t. But it seems they need to drain the pools, put in a sequestering compound to manage the copper, then all should be a normal azure blue again. Read more here.