Misschien is het deze:
Cladophoropsis, Green Wiry Algae
Species in this genus, and related ones, cling to the rock, and spread from a runner. The branches do not get tall, and they are often found with hobbyist frags or on live rock.
Manual Removal: Difficult. Macros that have fragile runners and creep along the rock are the hardest to manually remove. Do the best you can. Get a dental pick and get it all the first time and be done with it.
Clean Up Crew: Rock Boring Urchins, Emerald Crabs, Turbos, and Sea Hares occasionally pick on it, but don't seem particularly interested in it.
Starving it out: It seems to be particularly good at adapting to nutrient lulls, and it is unlikely that a small amount of the algae here and there will be starved out of your tank.
Fortunately these algae species tend to grow slowly, and aren't particularly common.
We distinguish this from Green Turf Algae by keeping this heading limited to green algae that creep along the rockwork, rather than grow up from it.