In a statement, FINA, the world governing body for Olympic aquatic sports including swimming and diving, says that pH levels were the explanation for why the diving pool at the Maria Lenk pool turned bright green before Tuesday’s competition.
The “water tanks ran out (sic) some of the chemicals used in the water treatment process,” the statement read, which pushed the pH levels of the water outside of the normal range.
According to most pool manufacturers, the optimum pH for pool water is 7.4 – the same as the pH in human eyes and mucous membranes. In theory, a pH of 7.4 will give good chlorine disinfection while minimizing the impacts of the chemicals on the human body. Generally, between 7.2 and 7.8 is considered an acceptable range. Tests at the Olympic diving pool rose to 9, a more alkaline reading, which allowed green-colored algae to grow.
Venue management shocked the pool to a normal level just two hours before the competition began. FINA says that the FINA Sports Medicine Committee conducted tests on the water quality and concluded that “there was no risk to the health and safety of the athletes,” and as such decided to proceed with Tuesday’s diving events anyway.
Maria Lenk is home to both the water polo preliminary and diving competitions, but the two events are held in side-by-side pools in the same complex.
FINA can confirm that the reason for the unusual water colour observed during the Rio 2016 diving competitions is that the water tanks ran out some of the chemicals used in the water treatment process. As a result the pH level of the water was outside the usual range, causing the discolouration. The FINA Sport Medicine Committee conducted tests on the water quality and concluded that there was no risk to the health and safety of the athletes, and no reason for the competition to be affected.