At the New York Times, "During Diving Event, Pool Transforms From Crystal Blue to Garishly Green":
Why is the diving pool water green? @vickihallch tries to get to the bottom of it. (The question, not the pool.) https://t.co/9BQv44wiXL— National Post (@nationalpost) August 10, 2016
RIO DE JANEIRO — An unsettling thing happened at the Olympic diving pool on Tuesday: the water inexplicably turned green, just in time for the women’s synchronized 10-meter platform diving competition.More.
Officials said they did not know what caused the trouble, exactly. But they declared the water had been tested and was not dangerous. It was an unsettling sight, appearing to become greener and murkier as the day went on, having been a lovely light blue on Monday.
The British diver Tom Daley, who won a bronze medal in the same pool the day before, posted a photograph on Twitter showing the contrast between the colors of the pools. “Ermmmm – what happened?” he said.
The adjoining pool at the aquatic center, used for synchronized swimming and water polo, remained its normal blue color, which made the extreme greenness of the diving pool all the more striking.
Meanwhile, diving practice went on as planned, and so did the women’s synchronized event. Competitors generally said that the swampiness of the water did not put them off their form, although they found it weird and puzzling.
“I’ve never dived in anything like it,” said Britain’s Tonia Couch, who finished fifth, along with Lois Coulson.
The situation overshadowed the news conference after the event, with reporters more interested in the state of the water than in the quality of the diving. Officials released a brief statement that did not address the main questions: what had happened, why had it happened so quickly, and why wasn’t there a simple explanation, given that this is the sort of thing that commonly happens to swimming pools?
“To ensure a high quality field of play is mandatory to the Rio 2016 organizing committee,” the statement said. “Water tests at Maria Lenk Aquatic Center diving pool were conducted and found to be no risk to the athletes’ health. We’re investigating what the cause of the situation was.”
The statement also said, “We’re pleased to say the competition was successfully completed.”
Officials at the news conference declined to take questions from the news media about the water.
Steve Henderson, who owns AAA Pool Service in Santa Rosa, Calif., said that although he was not an expert on Brazilian swimming pools, there were two likely causes: a sudden algae bloom, which could be eradicated by zapping the pool with extra chlorine overnight; or a chemical reaction between chlorine and a metal in the water, most likely manganese.
“If they have manganese in the water, you will get a reaction depending on level of chlorination,” Henderson said. He said that it was a normal occurrence, as even a slight imbalance can cause a violent color change, and not a cause of alarm.
Still, he said, he found it puzzling that officials at the Games did not have a better explanation...