Photo shows the green water in the diving pool of the Rio Olympic Games. (Photo/Agencies)
Olympic organizers said on Saturday they will change the water in one of the pools at Rio's Maria Lenk Aquatics Centre after it mysteriously turned green.
Officials said the pool would be drained and replaced with nearly a million gallons of clear water before the start of the synchronized swimming on Sunday.
"We are going to grab the water from the warm-up pool, drain the water out of the competition pool and insert the water from the warm-up pool into the competition pool," Rio 2016 director of venue management Gustavo Nascimento told a news conference.
"This will be done overnight and we will start preparing the competition pool for synchronised swimming, which is due to start at 11am."
The pool, one of three at the venue, is being used for diving, synchronized swimming and water polo.
Rio 2016 spokesman Mario Andrada said tests showed that the green water did not pose a health risk to athletes.
But he said the water needed to be changed for judges and competitors.
"Of course it is an embarrassment because we are hosting the Olympic Games," Andrada said. "It should be light blue, transparent. We could have done better in fixing it quickly. We learned a painful lesson the hard way."