As the Lincoln Reflecting Pool turned green with algae, officials are now using chemicals to fix it.

The National Park Service continued a push Tuesday to eradicate algae from the Lincoln Memorial Reflecting Pool as tourists and locals gathered to view the green-tinged water. The Department of Interior has deployed both a hydrogen peroxide treatment and nanobubble ozone technology,

The National Park Service is using hydrogen peroxide and “nanobubbles” to treat algae that’s been growing in the Lincoln Memorial Reflecting Pool since the water feature was refilled last week after a multimillion-dollar renovation.

National Park Service continues push to eradicate algae from the Lincoln Memorial Reflecting Pool as tourists and locals gathered to view the green-tinged water.