I've noticed this enveloping goo covering my caulerpa in the sump. I've also seen this matted thick film on a small part of 1 rock in my sump. When you blow on it with a syringe it flakes away. However, I haven't seen a way to get it off of the caulerpa other than just trimming the engulfed piece out. The picture below is after I cut it out of the sump. I am using a grow light (reddish Lowes LED) in the sump so I'm wondering if that is fueling this stuff. I've not seen anything like it in the DT. Anyone know what it is?