dark turf-like algae growth problem

[ultraxr]

I have some growth of this fuzzy, turf-like, dark algae on my rocks. Its only on areas exposed to the light, like the top surfaces of the rocks. a little bit on the overflows, but that's about it. None of it seems to be bothering or growing on any zoas or corals. I have a tuxedo urchin and it doesn't seem interested in eating that except coraline. Is there like a sea cucumber/hare, slug, etc. that can clean this up or something? Recommendations are very much appreciated. My lighting is a Tek-Light T5 8x54 watt fixture. It seems to be collecting free floating detritus on top of it.

Here are some pictures showing the algae growth I'm talking about.