What can I put under my brights?

[pseudorand]

My 120g is lit by 4 x Lumia 5.2 DIYs (each is a 5x5 grid of cree LEDs of 5 different colors). I have the two blues at 35% near midday. Everything else is dimmer.

In the pictures below, you can see that GHA loves this deeper in the tank. But way up on the rocks just under the light is barren.

There are likely multiple reasons, including urchin activity and flow, but it seems like some light-loving thing should be able to call that home.

What do I put right under that very intense light?

 

[Reefer5640]

Could be due to a lack of spectrum blending as well... as far as what to put under it, do you know what kind of par you’re dealing with?

 

[pseudorand]

No idea about Par, as I don't have a meter. The best article I've found so far is, of course, right here on R2R.

The bare rock in my photo is right under one of the lights and probably doesn't get much from the others due to angle. However, I have the different channel at different outputs, favoring the blues cuz I read corals like that sort of mood lighting but algae less so. With even those being at 35% max, I guess maybe only 50 par based on 1/3 of the approximate 150 par in the center of the tank in that article.

Perhaps my question is both how to adjust my lights as well as what to plant in the bright spots.