Algae is forming on the water in the newly refurbished reflecting pool by the Lincoln Memorial in Washington, D.C. (Bill O'Leary/WASHINGTON POST)

The National Park Service began draining the Lincoln Memorial reflecting pool Wednesday afternoon, the latest attempt to remove algae that had spread across the landmark and overshadowed the $34 million renovation of the site.

Carol Johnson, a spokeswoman with the National Park Service, said officials had made attempts in the past week to remove the algae, which began showing up in the pool about a week after its reopening. Johnson had said earlier that the Park Service expected a “break-in period” for the pool, but no one had anticipated the amount of algae that appeared.

Last week, officials began to filter out some of the algae. Most of what remained was dead, Johnson said, but the process of letting the algae disintegrate naturally could have taken months.

So officials decided to increase the ozone level of the pool. And after meeting with aquatic biologists and water resource management experts, they decided it would be better to drain, refill the pool and then recalibrate its ozone level.

The amount of ozone, which neutralizes the nutrient food for the algae, will be doubled. That should keep the algae from reappearing, Johnson said.

Previously, draining the reflecting pool has taken up to three weeks, but Johnson said Park Service officials think it can complete the work in a shorter time.

The cost of draining the pool and removing the algae is estimated at $100,000 and will require 65 contractors along with Park Service staff members working full time to complete it, Johnson said.

Access to the reflecting pool will be limited.

“This is a new state-of-the-art system, so there was going to be some trial and error involved,” Johnson said. “But we’re confident the higher ozone levels will work.”

Renovating the pool, which had major structural and maintenance problems, took two years.