No refugium on mine, not sure about Brian's.
My issue seemed to be triggered by using plain old treated tap water as I believe mine is high in silicates. After the crash last fall I've been using deionized water with no further problems. Except, I had a cuke die a few months back and did a quick 50% water change w/ plain treated tap and it started to rear its ugly head again but a bunch of syphoning and deionized water changes spread out after that made it disappear again, along w/ some Pura Phos for good measure added recently just to make sure.