Help....No Coraline Algae to Speak Of

[beginnersluckpg]

It grew before I changed the lights, I have 2 250 mh and 4 t5s. The lights I purchased from a friend whose rock is covered in coraline, I'm not worried about it showing on the glass, I do get a bit of real pale stuff on the glass but nothing on rocks at all. I'm more concerned with the rock, makes me winder what I'm missing