The 'green stuff' is some kind of filament algae that only seem to grow on that one piece of LR. Don't know why, it is totally covered, but it doesn't bother the rest of the tank too much.
I am going to move that piece of LR to my 'sumpfugium' because it is rampant with copepods and isopods, that is the main reason I have not tried to get rid of that algae. They seem to feed off it.
I live in Southeast MI, 30 miles south of Ann Arbor. Just North of Toledo, OH.
Thanks for the encouragement,