Long story but rebooted a display tank. Fuge, sump and plumbed in 30 are old. I assume this is some form of green hair algae. Not unexpected to have some growing pains. One thing I don't understand is why it is only in the display tank which contains a CUC. Light spectrum in fuge should be more suited for it I would think but none. 30 gallons pumbed into the system has none and only has a clown and bunch of anenome. Is it thriving on something on the rock itself? I cycled rock for some time in a tub but I imagine some nutrients stayed on the rock. Thanks in advance.