There have been a few people who have tried Refugiums with Zeo. Those who fought hard to keep their Macro alive found they also saw increased nitrate and phosphate levels in there display tank. I can only assume that was because the Zeo-bacteria population collapsed.
I read a bit about this because I had plumed in a tank to act as a Refugium when I biult my tank. It's now a frag tank.
J