Algae on Back Wall of 32G Biocube

[William Morris]

Wondering if the green algae growing on parts of my back wall are a help or hindrance to the tank.
Don't really want to try scraping it or brushing it off in fear of raising nutrients.
You can also see a little bit of the beautiful dark maroon algae that grows all over my rocks.

 

[xxkenny90xx]

Is it hard or soft? Fuzzy or slimy?

 

[William Morris]

It's hard and not fuzzy or slimy - great question.

 

[William Morris]

Here is a view from the top - noticed in the last month or so the light green color algae (?) covering the rock work on top. It's not slimy.
Tank is 3 years old.
Phosphate: .06
Nitrates: 15
Calcium: 450
PH: 7.98
Corals are doing great. All LPS

 

[William Morris]

Anyone have an idea or opinion?
Wondering if the shift in color on the rock is from lowering the white light and bumping the blue?
Would that affect the coralline?