Reef Tank - I can't win

[Antrias]

I'm looking to see if anyone has any advice for me in my current situation. I recently added some items to my Reef tank - which I have had running with corals, anenome, two tangs very successfully for about 9 months. I decided to get some more stuff a few weeks ago. I added an Elegence Coral (unsure of Aussie or Indi), Maxima Clam, Flame Angel and Leopard Wrasse. The stock all came frame the same tank from the store and I was told everything had been there for a long time (30+ days). Which was perfect because I needed stuff that could go straight into my tank or I didn't want it.

Well simply put I'm an idiot and should just not listen to what they say. The clam died 5 dies in - was 100% fine opening and looked amazing until i came home in the 5th and it was dead. 10th day Elegence coral tanked it and died. 12th day Flame Angel has 1-2 visible spots of ich. Leopard Wrasse looking great still. All the fish eat like beasts eating my garlic and Selcon enriched shrimp / Thera-A NLS pellets... ect

Basically I think I'm screwed. What should I do with my fish at this point? All my other fish have no visible ich but at best I can setup a 10g QT. Last time i tried to QT my last flame and do hypo salinity for my previous tank it just simply got 10x worse and died.

I was thinking of getting a UV Sterilizer but I read mixed things about those.

My tank seems to have great parameters

0 Nitrite
0 Nitrate
0 Ammonia
390MG cal
PH 8
Phosphate - I dont trust my test kit for phos - says 0
Salinity 1.26

I use Nitra-Guard so I always have perfect Nitrates .. I don't know what to do I'm afraid I just doomed all my fish to death by ich