July 3, 2015
The Blue Lagoon at Willamette View, Portland, Oregon
After the upper ponds were drained an resealed, an copper algicide was added to the water as they were being refilled. In addition to this colorless chemical, a concentrated blue dye was also added. Just one cup was all it took to created this tropical lagoon. The dye keeps some sunlight, which promotes algae growth, from hitting the bottom of the pool.
Residents of Willamette View who don't want to brave the 95-100º heat can see the from the common rooms of the Terrace, or just click on the photos below to enlarge them.