Coralline Algea identification

[YandyRiv]

Good afternoon From Spain,

Can some one help and tell me if this is coralline algea. I have a 32 gallon biocube 6 months old live stock i have 2 clowns 1 red fire firefish 1 cleaner shrimp 1 fire shrimp and 3 emerald crabs.

tank parameters are
Amonia - 0
Nitrite - 0
Nitrate - .10
phosphates - .25 ( cant seem te get it down i feed minimum and every other day ) dont know how accurate the test is.
Calcium - 500
Magnesium - 1450
PH - 7.8 - 8.0

 

[Highgrade]

Looks like a dead piece of coralline.

 

[cloak]

It might be... Coralline algae does come in a wide variety of colors.

 

[YandyRiv]

Looks like a dead piece of coralline.

It actually started like that it was never another color.

 

[Highgrade]

It actually started like that it was never another color.

Usually if it is brown/green or white its dead coralline.