(COLORADO SPRINGS) — Prospect Lake in Memorial Park has reopened to visitors following a mandatory closure for testing of blue-green algae.

The lake was closed on Wednesday, July 24, after a test came back positive and confirmed the presence of mycrocystin toxin, which is produced by cyanobacteria, also known as blue-green algae. Blue-green algae can make the water look green, turquoise, gold, or red. It can also look like thick pea soup or spilled paint on the water’s surface, and be made up of small specks or blobs floating at or just below the water’s surface.

The increased bacteria in the water can produce a toxin that is harmful to humans and pets, which prompted the closure. In order to reopen, the lake underwent a mandatory closure, and had to undergo two consecutive negative tests.

“We would like to thank the public for their understanding and patience as we worked to address the algae blooms in Prospect Lake,” said Erik Rodriguez, senior environmental, health and safety specialist for Parks, Recreation and Cultural Services (PRCS). “The health and safety of our community is our top priority and with the extra chemical-free treatments, we are pleased to announce that the lake is now open again for everyone to enjoy.”

Visitors can once again swim, bathe, paddle board, tube, water ski, and boat in the lake.

And while this is good news, algae blooms are still possible in the late summer months when conditions are right, including higher temperatures. The City of Colorado Springs asks that the community remain vigilant, and exercise caution by not drinking the water, keeping children and pets out of the water and avoiding any contact with algae that may be present.

Fishing is permitted but anglers need to rinse fish with clean water and properly dispose of organs when processing. Boaters must also avoid any visible algae contact. PRCS staff will continue to monitor and perform weekly testing to ensure safe, recreational water quality levels set by the CDPHE and the EPA.