The National Park Service/Interior Department attributes it to "residual algae" from supply lines that sat dormant for ~8 weeks during construction. When the pool was refilled (using city water this time), it carried over contaminants. They're skimming, vacuuming, and using hydrogen peroxide to treat it, claiming the new system will prevent future issues once cleared.
It's mostly nature + engineering realities, not a single person's "fault." Algae has plagued the pool for years due to its design (built in the 1920s on marshy ground). Renovations under different administrations haven't fully solved it because it's a massive, open, non-chlorinated reflecting pool—not a swimming pool. The Trump administration highlighted the project as a fix for prior neglect, but the quick rebound fueled partisan memes and criticism (e.g., "swamp" jokes). The dark paint choice amplified the optics, though heat waves played a role too.
So won't it have made more sense to consult someone before wasting 14 million dollars painting the , pool, pond, lake

? Hmmm ? How about flushing the lines out before refilling it, any moron knows that. but as usual nobody knows more about pools then trump
https://www.yahoo.com/news/science/articles/4-problems-manually-pouring-hydrogen-112042852.html?fr=sycsrp_catchall