Viewers and experts alike were baffled when the Olympic diving pool in Rio suddenly turned a murky shade of green earlier this week.
The bizarre transformation caused much confusion and prompted speculation over what exactly had cause it.
At least one athlete even claimed that the pool “smelled like a fart” and the competition pool also began to change colour.
Theories ranging from a reaction with suncream to athletes urinating in the pool took over the internet - but at last, the mystery has at last been solved.
According to the New York Times, someone mistakenly added 160 litres of hydrogen peroxide to the water.
The blunder neutralised the chlorine’s ability to kill “organic compounds”, which may include algae.
Hydrogen peroxide is effective as a pool cleaner but not when used in conjunction with chlorine.
On Saturday, organisers began the mammoth task of draining the water from the competition pool and replacing it with water from a practice pool. The diving pool, which is not required for further events, will not be drained.
According to the Associated Press, Mario Andrada, a spokesman for Rio 2016, said the “radical measure” was necessary to ensure clear water for both judges and competitors during synchronised swimming, an event that requires swimmers to spend much of their time underwater.
He stressed again that the water posed no risk to the health of the athletes.
An adjacent, smaller pool will continue to be used for the diving competition, even though it remains murky.
Andrada said: “Of course it is an embarrassment because we are hosting the Olympic Games.
“It should be light blue, transparent. We could have done better in fixing it quickly. We learned a painful lesson the hard way.”