Blue green/black algea help!

[Jammie]

I have blue/green/black algea growing in my sump/refugium only. What could be causing this? All of my parameters are great except calcium could be higher. S uh suggestions on how to handle this?

 

[reef lover]

To start theyll want a list of current parameters to see if we can narrow it down and pic is always helpful.

 

[lapin]

A picture with normal lighting would be helpful. How old is your system?