Hi LR - please see the photo I've attached. This stuff recently popped up on my newly cycled tank, at around the 75 day mark in the cycle. My ammonia, nitrates have all been next to 0.0. I'm still dosing with RedSea NOPOx. I've sucked out a big batch of this stuff once, and it has regrown in a few days. It is even down in my sump with no light. Actually, today, it seems like the majority of the bloom is down in my filter socks - more in that sump area than in my display.\n\nAny ideas on identification and remedy? RedSea Reefer 250.