Was it an Algal Bloom?
Nobody knows for sure but it seems likely that the Rio Olympics pool maintenance team ran out of chemicals to control the pH of the water which resulted in an algal bloom turning the pool green. To prevent the same happening in the water polo pool, the maintenance team have dosed high levels of chlorine into the pool, which is now causing issues for the water polo teams.
The incident would have been prevented with the use of an online controller such as Pi’s AquaSense swimming pool controller. Plus if the chemicals had ran out, such a system would have gone into alarm and enabled the maintenance team to prevent this from happening.
Pi’s AquaSense measures pool pH and chlorine levels and controls these with chemical dosing. The AquaSense can also be accessed remotely over the internet, enabling data, alarms and setup information to be sent directly to your computer via a 2G/3G modem or via a TCP/IP Local Area Network (LAN). Maybe the Rio Olympics pool maintenance team should have purchased a Pi analyser?