hmm, good points.
My thought was that the live rock was enough to break down the waste, yet not enough to prevent spikes and the spikes are what may have been the initial stressor for the corals. That was my thought.
and the 80 ppm
of nitrate isn't what got my attention considering it does accumulate over time, it was the doubling of the levels in a day or two that I took notice of and indicates some major issues going on and for it to rise that fast would indicate that ammonia and nitrite were also probably elevated, but harder to detect or "catch".
I guess we can all just agree is sounds like multiple things were done within a really short period of time and it has resulted in a mess.
Another cautionary tale of why it is important to take things slow and methodical when making major changes.