Cyano or Coralline?

[Saul2309]

Morning everyone

I’ve had this 75g tank setup for three weeks now, half of the rocks were moved from my estabilished 20 g and also I used a bit of sand to seed it and left for a little bit of the filters of the old tank into the new tank’s sump.
Some of the new rocks i had purchased were dry and some other were live( the one on the pic was one if the live), I am now wondering if that on top of the rock is coralline algae from my 20g rocks or cyano.
So just that I can get ready for an outbreak and contain it as much as possible.

 

[Dbichler]

Looks like normal aging of rock to me not coralline or algae.

 

[Saul2309]

Looks like normal aging of rock to me not coralline or algae.

The rock was grey as the color in the bottom right but that purplish color wasn’t there till i noticed yesterday night, also I did feed phyto for the first time yesterday in the morning, dk if that would make a difference

 

[Mr. Mojo Rising]

its not coraline, coraline doesn't grow that fast, maybe the beginning of some algae or cyano. The rocks will change colors as the tank matures.