Just a follow up... ORP held 280mv through the evening, this morning I bumped the controller up just a touch and now holding at 300mv. Likely won't bump it again for a few days to let things settle in, the skimmer is still producing heavy thick foam but little watery skimmate, instead it's a dry very dark brown splatter all over the collection cup. That's going to take some scrubbing if it goes too long.

So far everything looks great, water clarity (though subjective) appears to be improving.