Rock turning grayish blue

[sen5241b]

Every bit of rock in my tank was coated with pink coralline and after I put a MH over it much of it died back. Same exact thing happened with my BC29. When coralline dies, it turns white of course but now a few months later the white is turning to a grayish blue color in some places. What are the grayish blue patches?

 

[little_fish]

Interesting, Ive never seen that before. Are they hard or easy to scratch off?

 

[sen5241b]

Interesting, Ive never seen that before. Are they hard or easy to scratch off?

Very good question. I was able to scratch it off with a metal utensil. Some kind of purple coralline?

 

[little_fish]

I have no idea, perhaps some sort of coralline skeleton that is now coloring up? Kinda like dry rock does after being in the tank for a few months.

 

[Smitty]

Yeah, that's new to me also bro.