For days, workers have been trying to rid the Reflecting Pool of algae after a more than $14 million renovation that President Donald Trump said was “done properly” and “could last for 100 years.”

But now workers have another problem to contend with: peeling paint. On Thursday, a sheet of the pool’s surface — painted in “American Flag Blue,” a color selected by the president — was seen floating in the water on the north side of the pool. It undulated in the water as curious tourists gathered, some of whom had come to see the green algae.