First green water. Now stinging chlorine. Athletes struggle in Rio pools

It turns out the murky green water was just the start of athletes' woes at the Rio aquatics center.

Now the water athletes' have to contend with eye-stinging amounts of chlorine saturating the pool, according to several competitors' accounts.

Team USA men's water polo captain Tony Azevedo and Hungary's Gergo Zalanki have both complained of burning eyes and poor vision in the water since officials tried to address the color issue, as has Australia's Richie Campbell.

“I could barely open my eyes for the final quarter,” Azevedo said after his team beat France on Wednesday. “This is the Olympic Games and they are putting so much chlorine in the water that people can’t see. You can’t have that.”

“My eyes hurt from the water, it’s not good,” Zalanki also told reporters after his team drew 8-8 with Greece Wednesday. “It feels like they added more chlorine to the water, but I’m not sure. I’m used to it because we have a lot of water like this in Hungary, but I think there might be something else wrong too.”

The accounts sound somewhat contradictory to officials' insistence that “there’s absolutely no risk, no effect for athletes who will compete in the pool.”

Tony Azevedo struggles at the Maria Lenk Aquatics Centre. Credit: Tom Pennington/Getty Images

So what exactly is going on in the latest saga to plague the troubled games?

Here's what the officials say: The green color in the diving pool comes down to "the water tanks running out of some of the chemicals used in the water treatment process," according to FINA. "As a result the pH level of the water was outside the usual range, causing the discoloration."

A “proliferation of algae” caused by hot temperatures, rain and a lack of wind has compounded the issue, Rio Olympic spokesman Mario Andrada said.

The pools, which host diving, water polo and synchronized swimming and, unlike the main swimming pool, are open to the elements, were treated overnight Tuesday. That is improving alkalinity levels and will get the water back to blue, Andrada insists.

The solution, though, seems to be worse than the problem. Officials haven't specified exactly how they are trying to turn the waters from green to blue, but several experts have speculated that they tried to "shock" the pool with chlorine.

Experts test the waters. Heavy rain slowed the flow of new chemicals added to the water which was also green in the pool used for the synchronised swimming and water-polo. Credit: CHRISTOPHE SIMON/AFP/Getty Images

How pools are kept clean - and blue

Contrary to popular belief, you can't just chuck chlorine at a pool and hope for the best. As Deadspin points out, pool water needs to maintain a delicate pH balance - achieved through filters and chemicals and careful inspection to ensure that the chlorine effectively kills algae and other bacteria. It's a fine art and a balancing act that needs constant attention.

Rio's main problem is that events are taking place almost constantly; officials don't have a chance to fully shut and drain the pool. So it's likely they just upped the chlorine to try and blast that embarrassing color away.

Erica Andresen, the associate director of George Mason recreation facilities, which operates a competition pool, told the Washington Post she thought officials "probably super-chlorinated" the pool. If the water wasn't run through the filtration system enough times it could burn competitors' eyes, she said.

"The people in charge of maintaining the pool and checking could and should have done more intensive tests," Andrada said on Wednesday.

The Maria Lenk Aquatics Center was built for the 2007 Pan American Games and repurposed for Rio 2016. It was shut down for three months following a test event in April.

Water polo continues at the center for the rest of the week, with more diving and synchronized swimming to come.