How and why algae clouded Trump's vision for an 'American flag blue' Reflecting Pool

National Park Service employees use a vacuum pump to clean algae off the bottom of the newly repainted Lincoln Memorial Reflecting Pool on Tuesday. Chip Somodevilla/Getty Images hide caption toggle caption Chip Somodevilla/Getty Images WASHINGTON — The Lincoln Memorial reflecting pool is once again making headlines, this week for turning green. The Washington, D.C. landmark was refilled with water earlier this month after President Trump had its neutral grey bottom repainted "American flag blue." The multi-million dollar project produced subtle results in the eyes of many observers, even as Trump and Secretary of the Interior Doug Burgum — whose agency managed the renovation — touted its success. In recent days, however, the pool has taken on a verdant hue — the result of algae blooms that experts say are to be expected in these conditions. "It's called 'New Pond Syndrome,'" says Steve Goodale, a Canadian swimming pool specialist known online as " Swimming Pool Steve ." "It's a known thing that happens when you take a natural, clear body of water like this that sits in an open air environment and you try to start it up, very often you end up with green water almost immediately." Goodale says the process took longer — a matter of days — to unfold in this case likely due to the sheer size of the pool, which measures 2,030 feet long and has a surface area of approximately 338,000 square feet. …