after months of neglect

youre taking this like you were being attacked. seems we were asking pertinant questions to try and help you out. best of luck , hope your corals thrive once again.

 

I don't want to cause an argument or discourage the OP from revitalizing their tank (Sounds like your on your way back to health) but I agree that the water parameters are most likely far from perfect. What many people forget is that our tank water contains much more then just nitrate, nitrite, ammonia, buffers, Ca and Mg. Those can all test perfect and there could still be major issues. The fact that you neglected water changes, a lot of your coral died and you have a cyno outbreak leads me to believe something is out of wack. IME, sps, lps and soft corals can survive on light along, at least without direct feedings. So you probably had some sort of toxic buildup in the tank.

I think the advice given has been good. Do a water change and get back on that schedule and watch what you feed. Maybe run some ferric oxide for phosphates. I don't think this is a blame game, very few of us have perfect water parameters all of the time. Use this as a learning lesson and move on. Good luck.