I love how a simple thread has devolved into debate; i love it!
As I conceptually think about what has been discussed and some of the skepticism, perhaps we need to better categorize different types of environments and outcomes.
Environmental influencers:
1. use of mature live rock
2. use of well established sand
3. dry rock
4. bare bottom
5. etc
Outcome:
1. ammonia reduction for purposes of keeping fish alive
2. ability to keep acropora and other sensitive species
3. etc.
I think trying to bucket all there primary influencers and outcomes will mean more points for disagreement. Just a thought. For example, if the outcome we're trying to benchmark against is the ability to keep fish, then perhaps nitrite does not matter unless it reaches an extreme concentration at which perhaps the nitrite itself is not the cause of fish mortality but something else that is influence by extreme concentrations of nitrite.
On the flip side, perhaps this calculus all changes when we talk about acropora. Perhaps this changes when you have extremely well established coral colonies that are used to certain conditions for 3-5 years and you make a sudden change.