I.D this algea

[MikeB]

This algae is bright neon green, crusty and difficult to remove. I have to scrape off and when removed it is very hard. I also have some red coraline starting to grow.

 

[nitro069]

I had the same algae growing in my tank when i first started my tank. I believe it is another form of coralline algae. mine went from that super bright,  toxic looking green to purple coralline. looks wicked, almost alien like