When everyone went to bed Monday night in Rio de Janeiro, the Olympic diving pool was a nice shade of blue.
When everyone started piling in Maria Lenk Aquatics Stadium venue Tuesday, the pool was a gross shade of green.
PHOTOS | Olympic diving pool turns bright green
The worst part, no one knows why.
Ermmm...what happened?! pic.twitter.com/pdta7EpP2k
— Tom Daley (@TomDaley1994) August 9, 2016
Olympic dive pit shouldn't be this colour green I wouldn't be diving in it lol. Water polo pool look a lovely blue pic.twitter.com/bbBp68sLaz
— Claire Martin (@Clairey2674) August 9, 2016
The #Olympics diving pool is green in honor of #Ghostbusters actress @Lesdoggg coming to visit with slimer green pic.twitter.com/EM8oEMvkyU
— Hashish (@hashphish) August 9, 2016
Water polo pool on left... Diving pool on right. One blue, the other one green. Strange. #green #RioOlympics2016 pic.twitter.com/y5FDGzM8Wr
— Andrew Cropper (@andrew_cropper) August 9, 2016
So the #Rio2016 #diving pool is suddenly green and literally no one knows why. Just switched over to the #dressage 😯 pic.twitter.com/1UsVaDcm86
— Simon Halewood (@simonhalewood) August 9, 2016
Right next to it is the water polo pool, which still looks perfect.
According to some fancy Google searches, pool water can turn green when the chlorine level falls below a certain point.
Likely the pool staff needs to add some chemicals to the pool because the green color is usually because of algae growing in the water. However, they say they tested it and found nothing wrong with it.
The water quality at the Maria Lenk Aquatics Centre was tested and there were no risks for the athletes. We are investigating the cause.
— Rio 2016 (@Rio2016_en) August 9, 2016
It doesn't seem to be concerning too many of the swimmers. They are still diving right in.