It looks as if the water polo pool is turning green with envy.
The men's Olympic tournament resumed Wednesday in green-tinged water after the diving pool at Maria Lenk Aquatics Centre turned a dark green the previous day. There was no sign of any water quality issues with the water polo pool during the first day of the women's competition Tuesday.
A decrease in the alkaline level in the diving well Tuesday afternoon led to the green color, organizing committee spokesman Mario Andrada said. He added that the pool for water polo and synchronized swimming is being affected in the same way.
"We have treated both pools during the night and the alkalinity levels have already improved," Andrada said. "We expect the color to be back to blue very shortly."
Maybe not, according to a U.S. pool expert.
"Once you get behind, it gets hard to get back in front of it," said Jerry Wallace, chairman of the California Pool & Spa Association, a trade group.
According to FINA, the world governing body for aquatic sports, water tanks ran out of some of the chemicals used in the water treatment process, causing the pH level to go outside the usual range, leading to the discoloration. Andrada and FINA said there is no risk to athletes competing in either pool.
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"Just from TV and pictures on the computer, it looks more like an algae than alkaline problem turning the water green," Wallace said by phone from Sacramento, California.
Andrada said algae also is an issue.
"The algae makes the water look green. We kept the same level of maintenance as we did before, but we had far more athletes," he said. "We had more dirt in the water and that generated more algae."
Wallace said if there's a reaction with iron in the water, the pool would turn a translucent green. But a murky green color, as seen in the diving pool, would indicate an algae issue. Wallace said some strains of algae will grow even in water that is balanced.
"If they're cleaning the diving pool and then using the same tools in water polo, they could contaminate it," he said. "Algae spores can be transmitted."
The warm and humid climate in Rio de Janeiro could be a factor, too.
There are no such problems at the swimming venue, a temporary facility with its own filtration system. The diving and water polo pools are part of a permanent facility opened in 2007.
The black lines at the bottom of the water polo pool were clearly visible as play continued throughout the day, and there was no evidence of the color affecting the action. But a couple players said they could tell the chemical mixture is off.
"They put way too much chlorine," U.S. captain Tony Azevedo said. "The last quarter, I can barely open my eyes."
"Everyone's obsessed with the green water. Who cares about the green water?" Azevedo continued. "Sometimes you can have green water, black water, it doesn't matter as long as it's safe for us. You throw in too much chlorine, all of the sudden you can't see. These are things that, it's the Olympic Games, you can't have that."
Hungarian water polo player Gergo Zalanki got some drops for his eyes after an 8-8 draw against Greece. But he wasn't sure chlorine was the problem.
"Yes, it feels like that, but I don't know," Zalanki said between sniffles. "In Hungary there's lots of water like this. It feels like lots of coloring, but there's something different."
The Maria Lenk Aquatics Centre, named after the first Brazilian woman to compete in the Olympics, was renovated before the Rio Games. The major upgrades included new springboards, a refurbished medical center, new hydrotherapy baths and two new warmup pools. There is no mention of any update to the water treatment system in the venue description.
Andrada said a test event at the facility did not account for increased use for longer periods during the Olympics.
"We probably failed to note that with more athletes the water could be affected in a different way," he said.
The green diving pool water befuddled swimmers and viewers alike on Tuesday, including Tom Daley, who won bronze for Great Britain.
Observers on social media, meanwhile, were quick to poke fun at the pool's discoloration.
The women's synchronized 10m platform finals went on as planned Tuesday despite the green water, with the Chinese duo of Chen Ruolin and Liu Huixia coming out on top.
Here's an image of what it looked like from above during Tuesday's competition:
And here is what it looked like on Monday: