What is this?

[evrydayzawrkday]

Howdy!

As a precursor, this is not my current tank but one I had a few years back. I moved, broke the tank down, but I am curious as to what this stuff is. Saw the picture, thinking it was Cyano & Green Algae but curious as to what everyone here thinks.

I don’t recall the tank parameters but I do remember some of the characteristics…

- lots of air bubbles on the rocks while lights were on
- at one point I took the rocks out to scrub. The green stuff was slimy, but the purple was tougher and stained.
- It somehow never affected the sand bed.


Sorry, I know this is a long shot but curiosity is getting the best of myself

Edit
I do recall using Chemiclean since I thought it was Cyano (my Nitrates were elevated, but I don’t remember what exactly they were) but it did nothing. A black out didn’t either.

 

[AnotherReefHobbyist]

Honestly it looks kind of like coralline to me, but not an expert so I will let others weigh in.

 

[evrydayzawrkday]

Honestly it looks kind of like coralline to me, but not an expert so I will let others weigh in.

Yea, that’s what I thought as well but the green really put off a lot of micro bubbles which made me think Cyano initially.

 

[AnotherReefHobbyist]

Yea, that’s what I thought as well but the green really put off a lot of micro bubbles which made me think Cyano initially.

That’s the only thing that doesn't add up

 

[CanuckReefer]

Honestly it looks kind of like coralline to me, but not an expert so I will let others weigh in.

Green Coraline to my eyes.....the green starts out a bit slimy, then eventually goes purple/pink and harder. The observation it's not invading the sand bed also leads me to say likely this....

 

[evrydayzawrkday]

Green Coraline to my eyes.....the green starts out a bit slimy, then eventually goes purple/pink and harder. The observation it's not invading the sand bed also leads me to say likely this....

even with the air bubbles the way they were?