Green Algae? Green Coraline? Or Neither?

[mamacta]

There is green all over my rocks, shells and some on the sand. It is hard and does not scrape off. Also looks to be some pink/purple starting to grow on some rocks and shells. None on any plastic though. No idea if this is good or bad?

 

[KrisReef]

Looks like the beginning of the "ugly phase" that happens fairly quickly after a new dry rock tank is set up. Only time will tell what's coming next.

 

[Reefer Matt Verified Media Partner]

Looks okay to me. It will go away, and coraline will take over. Part of the "ugly phase".