[JWClark]

I think w/ ROX alone it is fine. I think what is going on is that, over time, the GFO pieces are locking together like a puzzle and eventually stop tumbling completely. W/ Rowa it was good for a week.

Another thought: I installed the black sponge on the top screen after the first GFO dissolved (I think the regular GFO is just too soft). I haven't removed this and, after a week, it was orange from the previous GFO dust. This dust has settled in the sump so when I stir things up it gets into the reactor. I'm wondering if this has restricted the flow through, contributing to the slow down in the tumbling. Will remove this week end.