What are these green spots on glass

[KSum89]

I had about 2 of them now theres a few more small spots on the front glass inside the aquarium. My mag float wont scratch it off and when i try to scrape it off with my fingers that wont work either. What is it and what causes it?? Its greenish yellow & im sure its not hair algae.

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[soccerbag]

Hard to tell from the pic, but I think it's just a green type of algae that can grow on the glass. And you're right, most magfloats will not get it. It will come off easily with a razor blade (or blade attachment with your magfloat). It's common though.

 

[KSum89]

Ok thanks!

 

[Reef Breeders Verified Sponsor]

That happens to me, every week or so I have to razor it. Basically all the weak mag float algae builds up until it is too strong for the magnet.

 

[Troylee]

It's corralline algae the most common color... Green..