Mass Coral Death

[Cal_stir]

http://www.marinedepot.com/md_educationcenter.html

Here is an article on getting rid of dinos, scroll down to knowledge base.
I had an LPS die off a while back, never figured out why, I ended up fragging all the dead stuff and removing it and eventually it ran its course.
the ammonia is probably aggravating your situation, Amquil will detoxify the ammonia.