RTN=Rapid Tissue Necrosis
STN=Slow Tissue Necrosis
I definately think salinity could have played a major factor in your loss, as well as other parameters. I have been having some issues with STN and have found some of my params out of balance, Mag to high, calcium high in relation to low alk, salt creeping up to 1.029 due to manual top off but not often enough...so I am hitting each thing as best I can. I just set up a top off unit. I am going to start mixing two kinds of salt for make up water. My salt mix is high in mag, low in alk and that coupled with the Ca Reactor is depressing my alk and shooting my calcium up in relation to the low alk. All of these things, I believe, are contributing to some STN over the past 5 months, often starting up after a water change. It has been hard to get a handle on, the mixing of two types of salt is the next step to see if I can get things more stable. Aggghhhh, I hate chasing numbers but I have to address the issues. Stability is the key, just like you said your other corals became accustom to the environment. Sorry for your losses.
