Critters? Or Algae? Need help with ID

[ReefGirl50]

I noticed one of these on my glass a few days ago. Today there are about 20 of these flat discs on the walls of my tank. Does anyone know what they are and what I should do about them?

 

[AydenLincoln]

Algae it’s fine you can scrape it off if you want.

 

[ReefGirl50]

Algae it’s fine you can scrape it off if you want.

Thanks. After posting I finally google the right combination of words to find “Green spot algae” — which seems so obvious now ‍