I completely drained and cleaned out the refugium yesterday, washed all the sand, shook off the macro and LR in rinse saltwater, and set it up anew. The cyano in that zone was so out of control, I figured I needed to reduce the nutrient level trapped in that compartment. It looks much better, but I'm very sore after working on that for over three hours. That would be the one drawback to a huge sump, when trying to reach the back portion.
My site has a few more pages updated.