Hello I was hoping someone could help me determine what might have happened to my fish. New to Saltwater aquarium but have had freshwater for 20 years. I have a 75 gallon FOWLR tank and within 48 hours almost all of my fish perished. The tank is around 6 months old. My parameters were good salinity 1.025, PH 8.0, Nitrite 0, Ammonia 0, Nitrates: 20. They were doing fine swimming around with no problems. Then my Flame fin tang started losing color and looked really pale and Butterfly fish looked milky white, like a film on scales. Wasnt sure is it was ich then they both perieshed.. Changed 20% of my water after and dosed with Ich Attack. Then today all of fish started perishing 2 wrasse, Coral Beauty, Springer Damsel, and now a percula clown, bubble tip anenome. Some showed signs of white specs or growths near mouth and some had fin damage. I only have one clownfish, lawnmower blenny and firefish (maybe) all not doing great. I lost my entire tank. I also have hermits, a sally foot crab, Saron shrimp, cleaner shrimp and Porcelain crab... who seem to be thriving. So i feel its some sort of fish disease... But seems to be extremely rapid development. Any advice would help... And what should i do before restocking my tank and how long should i wait. Also I did have a Cyano outbreak before, and dosed with Vibrant. a week ago. Thanks for the advice.