The bronze medallist wrote: “Ermmm...what happened?!”
British diver Tonia Crouch said the pool was so murky she couldn’t even see her partner Lois Toulson underneath the water.
And the unusual hue sparked some wide-ranging theories about what had really happened.
BBC presenter Dan Walker asked his followers to vote on what was the most likely explanation, with algae running neck-and-neck with urine as the most popular choice.
Despite assurances from organisers, there was plenty of concern over what outlandish fate might await those who dived in.
Dom Bevan joked: "This pool will sort the women from the lagoon creatures."
Others looked to the big screen and television to help solve the mystery.
Companies have also been getting in on the act after spotting a sneaky advertising opportunity.
Games organisers claim the pool could be back to a more normal colour by the time athletes return today.
