Can you ID this pond scum?

Asked July 26, 2018, 2:10 PM EDT

Our client brought in this scum that is growing in their pond. It started this year in June and they are wondering what it is, how to get rid of it, and if it can be prevented. It is covering about 80% of the pond. The pond also has a vinyl liner. Thanks in advance.

Alpena County Michigan

2 Responses

Hello! We checked with an algae expert in southern Michigan. From your picture, she said:

"...looks like basic periphytic blue-greens like Leptolyngbya and Phormidium among some dead stuff and perhaps freshwater sponge, which would be a find. Feel free to send some on, but it doesn't look like anything that could be toxin producing. Let me know if they want to send some my way, no report, no timeline, no charge."

If you are interested in sending in sample, please email me directly ( and I will provide the expert's contact information.

Hi Jo, thanks for your response. Do you know what they could use to treat the pond and or prevent it from growing?