Maybe cyano ?

[Denmark_ML]

Are that red thing beginning på cyano or what is this ?

 

[ZC aquatics]

Are that red thing beginning på cyano or what is this ?

Kinda looks like coralline which is awesome for the tank

 

[p1u5h13r4m24]

If it comes off the rocks easy than it’s cyano with it being a dark red/purple I’m leaning my more toward it being a cyano mat, but a bit tough to tell for sure from this picture

 

[Sophie"s mom]

If it comes off the rocks easy than it’s cyano with it being a dark red/purple I’m leaning my more toward it being a cyano mat, but a bit tough to tell for sure from this picture

I agree! THe OP should try to brush it off. If it easily moves, Cyano! If it is hard and stays in place, could be a variation of coralline algae.

 

[Denmark_ML]

Thank u.. what to do if its cyano?

 

[Sophie"s mom]

Thank u.. what to do if its cyano?

Manually remove with a syphon or turkey baster, water changes, and more flow.

 

[Sophie"s mom]

Thank u.. what to do if its cyano?

Have you checked your parameters? High nutrients and a lack of flow tend to be the cause. IF it is coralline , that is a good thing