Can anybody please

[NatsRams]

It started a while ago at a few locations. I tried manual removal a few times, but it is tough.

Pay no attention to the cyano….

 

[NatsRams]

Sorry, the title is incomplete. Could someone please ID the nuisance algae in the attached picture?

Thank you!

 

[ISpeakForTheSeas]

Looks like a Neomeris sp. to me.

Neomeris sp. This is a rare calcified green macroalgae that usually dies out in captivity. However, it has a rare chance to go invasive. Since it is calcified, I would assume few organisms could consume it besides urchins.
https://www.marineplantbook.com/marinebookneomeris.htm
https://www.reef2reef.com/threads/neomeris-annulata-reboot-only-option.279012/

 

[NatsRams]

Wow! That is it. Thanks for the ID.

There are several spots of it, some which can be dealt with as described by some (50% peroxide) in one of those links. A couple are on foundation rocks that would require major effort to remove. I’m not looking forward to doing it but I don’t want green shag carpet on the rocks like I saw in one of the pics.