The folks who are advocating for a floating pool in the East River have launched a very cool floating light sculpture — + POOL Light — off Pier 17 that will promote their cause and bring some attention to the water quality of the river.

Wait for nighttime to check out the Friends of + POOL‘s 50-foot-square LED installation. Designed by Playlab, Inc. and Family New York, the sculpture changes color based on the condition of the water. (This seemed like not the best way to promote an East River pool to me, but the + POOL folks assured me that the actual pool water that folks swim in will be filtered first.) It will be there till Jan. 3.

The sculpture is not actually testing the water, but rather reacting to data collected from NOAA that is then crunched by scientists at Columbia’s Lamont Doherty Earth Observatory. They created an algorithm that predicts bacteria in real time based on the NOAA data, weather stations, and a microbiology early warning instrument. The colors change according to the algorithm.

The shorthand: teal = good, pink = bad.

The teal means pathogens are present in the water and predictive Enterococci levels are safe for swimming (below 35 CFU). It turns to pink when those levels exceed swimming standards. The sculpture also animates, changing its direction based on the flow of current (clockwise when flowing north, counterclockwise when flowing south). The brightness, frequency and sharpness of the lights is reflected in oxygen, turbidity and pH, respectively.

Here’s hoping for lots of teal in our future.