Please help urgently!!! Fish Dead

[SterlingAce]

I have no idea what is going on and Im desperate to save my fish.I have been keeping fresh for 8years and started marines at the end of January.I currently have 3 setups:
100gal Reef setup:
5 Common Clown
2 Green Chromis
1 Coral Beauty Angel
1 Midnight Dwarf Angel
1 Royal Grammar
1 Yellow Tang
2 Bangaii Cardinal
2 Fire fish Magnifica
1 Decorated Firefish
1 Rocket Goby
2 Hermit Crabs
2 Cleaner Shrimp
1 Fire Shrimp
1 Coral Banded Shrimp
1 Decorator Crab
4 Turbo Snails
50kg Live Rock
Water:
23.7C
pH 8
SG 1.022
NO3 0
NO2 0
GH >16d
KH 10d

55gal FOWLR
2 Lionfish Volitans
1 Zebra Eel
1 Tesselated eel
1 Marine Betta
7kg Live Rock
23.4C
pH 8
NO3 25
NO2 0
GH 16d
KH 3-6
SG 1.021

43gal FO
Niger Trigger
2kg Live Rock
NO3 less than 10
NO2 0
pH 8.2
SG 1.027
Temp 26C
GH 16d
KH 6-10

Now to my problem,on Monday the black lion started developing a cloudy eye.I did a 50% water change and added epsom salt.The next day his eye looked 50% better,but I still did a 25% wc and added epsom salt.Yesterday both his eyes were completely white,did another 25% wc.This morning I found him dead. Just did another 50% wc and added some sera products.I know this is a very small setup for them but I have a external canister filter and an internal filter running.Also This weekend Im going to look at a 410gal tank to buy for them.
Also this morning I found my midnight angel lying on the bottom gasping and a few hours later he was also dead.
This afternoon I was planning on selling the trigger because he is aggresive and I wont be able to keep him in a small setup.As I was talking I placed a finger against the glass and like usual he tried to attack it.About 6hours later I found him dead underneath the filter with no obvious signs of illness.

All of the fish have been eating well,this is what I feed them : Hake fillet,octopus,squid,mussels,crab,bloodworms,lance fish,shrimp and prawns.The trigger and the FO setup only get fed every second or 3rd day.Does anybody have any idea what is going and what can I do to prevent any more deaths

 

[CCall]

Are all of your tanks linked together by a sump or refugium?
Did the midnight angel have any white or yellow spots on him with a film?
The angel sounds like Velvet. They eat really good and all of a sudden start flapping around trying to breathe.

 

[SterlingAce]

No the tanks aren't linked.About a day before the angel died he had about 5 white spots that looked like ick but was gone the next day.But everything looks better no more deaths.