I'm reviving an old post here, but my issues with STN have not subsided, regardless of all the changes that I have made, until recently. I've tried everything from correcting my salinity to eradicating asterina starfish.
My most recent solution was to hook up a CO2 scrubber. The difference is night and day, corals are recovering, polyp extension has doubled, major improvement in growth and encrusting of corals. With my tank in the basement, with multiple gas appliances, I think my CO2 was pushing so high that my pH was being impacted such that corals were just dissolving at the base.
So, to those of you who've, like me, tried everything to solve STN issues, try out a CO2 scrubber. Easy to make and a relatively low-cost way to rule out pH as the issue.
