Green water in Olympic diving pool seemingly spreads to water polo, too

By Pete Evans, CBC Sports

All the attention on the water in the diving pool at the Maria Lenk Aquatics Centre in Rio seems to have turned the adjacent water polo pool green with jealousy.

Attendees and TV viewers of the Olympic diving contests on Tuesday remarked on how the water in the pool had mysteriously turned green.

Rio Olympics spokesman Mario Andrada at a press conference Wednesday blamed a "decrease in alkalinity" for the colour change, but insisted the conditions were safe for competitors and spectators.

The "pH and chlorine levels are within the required standards," Andrada said, adding that both pools were treated during the night and alkaline levels have already improved.

"We expect the colour to be back to blue very shortly," Andrada said.

The international governing body for aquatics known as FINA says some of the water tanks at the Games simply ran out of a water treatment chemical, causing pH levels outside the normal range.

Problem spreading?

But then the third day of the men's water polo tournament began in green-tinged water, just like the diving pool the day before.

There was no sign of any issue with the water polo pool during the first day of the women's water polo competition. But a change in colour now would suggest the water issue is getting worse, not better.

Canadian coach Mitch Geller speculated it might be a build-up of algae due to a broken filter.

"They tried to accommodate the athletes here. And one of the things when we arrived was the water was very cold, so they'd been continuously heating it," he said.

"They kind of overshot the landing on that one because it got really warm. That also allowed for algae to bloom. They did try to address it, but because the time pressures, they had to try to react quickly, and it just backfired a bit."

Canadian pool experts say strangely coloured water is a common problem.

Alex Patlashenko, owner of Toronto pool maintenance company Swim Clean Pool Service, says green water is most often caused by algae.

Patlashenko said the problem can be addressed by "shocking the water" with higher chlorine levels than normal to clear it up.

Rob Wood, executive director of the Pool and Hot Tub Council of Canada, says a "chemical imbalance" can cause pool water to change colours, but it's typically easy to clear up.

For now, at least, the black lines on the bottom of the Olympic water polo pool are clearly visible, and there is no sign of any effect on the competition. But if the water gets any darker, it could become harder for the referees to determine what's going on underwater.

With files from The Associated Press and The Canadian Press