As British diver Tom Daley pointed out Tuesday, something looks...different about the Olympic diving pool.
The aquatics center hosted the women's synchronized diving finals on Tuesday, and yep, that water was GREEN.
Here's the same pool two days apart.
The picture below on the left was taken on Tuesday morning. The one on the right was taken later in the afternoon.
One British diver even said the pool was so murky, she couldn't see her partner underwater.
People watching the divers had questions, and journalists in Rio couldn't immediately get answers.
The shade of green looked a little familiar.
According to one pool manual reviewed by BuzzFeed News, cloudy green water is usually the result of an algae problem.
A disinfectant or algicide can clear up the problem.
Another possibility for blue-green water is the presence of copper ions in the water. This can be the result of a bad pH balance in the water and requires the addition of a sequestering or chelating agent to remove the ions.