Algae blooms, peeling paint, and a host of fixes from hydrogen peroxide to nanobubblers have made it hard to diagnose what’s wrong with the Reflecting Pool—let alone how to clean up the mess.

Enlisting nature to help purify the Reflecting Pool could be more patriotic and successful than tossing in more chemicals.

When the Lincoln Memorial Reflecting Pool turned green with algae just days after a $15 million renovation, the U.S.

President Donald Trump’s more than $14 million Lincoln Memorial Reflecting Pool renovation was completed just over a week ago, with its more than 300,000 square feet refilled with 6.5 million gallons ...