Been a looong time since the last update. Well, the tank is still there. It took almost 18 months(!!!) to get rid of most of the white slime. There is still some left, but just small amounts and it does not seem to be growing much.
Between frustration with the slime and the water restrictions in CA, I let the tank sit with minimal maintenance for over a year in the hope that whatever got into the tank would finally be used up. That seems to have happened. About half the corals have survived and some even thrived.
Also, I switched to a newer, bigger refugium made by Trigger Systems that is one thousand times easier to maintain. I can actually reach my filter socks without having to disassemble both the skimmer and the input pipes.
I'll see if I can post some update pictures in the future, if things keep improving.