Well, it appears as though things are back on track. All of my equipment is back online, the tank has been rehabilitated with all parameters in check. A few weeks ago I threw in some struggling colonies and they have all stopped STN'ing and are starting to colour up in their growth tips.
This digi here was completely brown and STN'ing. New growth tips show blue with red polyps. Appears to be turning into a "Superman Digi" maybe.
A few other random pieces I've picked up in the last little while.
I do miss "watching" these buggers grow. Grow little friends, grow!