Rio de Janeiro's Olympic diving pool has been closed Friday morning, British diver Tom Daley reported on Twitter. 

Diving pool is closed this morning. Hopefully that means we haven't been diving in anything too bad the last couple of days! ???

— Tom Daley (@TomDaley1994) August 12, 2016

But the pool has reopened, according to ESPN.com. 

"We confirm that diving training in Maria Lenk Aquatics Centre pool is canceled this morning," Rio 2016 spokesman Philip Wilkinson said according to ESPN.com. "The reason is that the water must be still so the pool can return to its blue color as soon as possible."

The green water is not new. The water at the Maria Lenk Aquatics Centre diving pool had turned green earlier in the week. 

Daley had tweeted his concerns earlier in the week. 

Ermmm...what happened?! pic.twitter.com/pdta7EpP2k

— Tom Daley (@TomDaley1994) August 9, 2016

Earlier this week, the FINA Sport Medicine Committee released a statement saying that water tanks at the pool ran out of certain chemicals. Athletes were not at risk, according to the statement.