Man o man, your tank is sooo unstable right now, it is not a surprise that you are having troubles.
Last month, you had no nutrients and a kh of 10, now you have nutrients- even slightly elevated p and a lower kh.
You've changed lighting as well...
I don't believe there is anything wrong with your water..
You are playing the reaction game. Whatever happens in the tank gets an adjustment.. this keeps you one step behind the tank and lets the problems dictate your actions... it's a tough position to be in.
I suggest stop worrying and fussing about the sick corals.. they are sick because of instability.
Sps can react immediately to stress and they can react very slowly to stress. You can never tell for sure if an sps is sick because of a stress that happened yesterday or last month and for you, you've had stressors recently and also not so recently.
I have done exactly what you are doing and completely wiped out a full sps system.
I sincerely feel that you need to step back and take a figurative deep breath and begin to concentrate on the basics. Stop worrying about the state of the corals. It is what it is right now. Concentrate on stability in the tank. Your kh is now in a good range, keep it there. Keep calcium stable and don't manipulate your nutrients anymore. Let them stay where they are.
Now, don't change the lights or anything for 2 months. You may still lose some corals but it won't be because of your current situation, it'll be from what has already happened..
Keep doing a 10 or 20% waterchange with a good salt and wait it out..
It is said over and over that bad things in a reef happen overnight and the good things take months. Truer words were never spoken.
You are in it for the long haul so take it a bit more slowly...
Hang in there and be patient..