Anyone else have the "problem" of not getting any coralline algae growth?

[new but handy]

Hey I've got quite a few dime sized spots on my glass and pumps.
But I've noticed that on the under side of my home-made rock and my base rock (in the shade) coralline is covering everything. Seems to like the shade.
It is growing on everything but it's much faster in the shady areas.
Just an observation.
I'm running 3 250w mh 15000k and pc actincts