New Tank Toubles - a Blues Song by Grady

Hey all I hope that you can give me some ideas of what to do here. I am new to the marine tanks. About 2 months ago I purchased a used 100 gal with several large coral rocks that had come from local waters. The person selling had the water and advised me that it would be a good idea to keep the water that was already set up to avoid the new set up time. I managed to keep almost all of the water for the trip across the island and set up the tank with the few inhabitants that came with the tank (a banded shrimp and two stars). They did well. About a week after set up I got two bule damsels and two clowns. They did great for two weeks so I felt like it was OK to add a few more fish. We added four Chromis, two Humbugs, and two anemonies. Again they did well. A couple of days later we added the final fish to our aquarium a butterfly. About a week later we started seeing odd behavior and physical changes (white spots). I thought that it might be ick, but our fish store identified it as fin rot thanks to our first dead fish. The butterfly was next to go just a day or so later this time with what they identified as marine ick. We have tested the water and treated for ick and fungal infections. These treatments required us to take out our invertibrates - which caused the death of one of the anemonies. We are now down to just five fish - the original two damsels, two chromis, and one humbug. We are currently treating, again, for fungal infections as one of the chromis is showing white areas just behind the head. All conditions seem normal.

Any thoughts? I did read that I should not have added the fish store's water when adding the new fish; rather, I should have "dripped" them. I have no idea what this process would be. I am stumped - it has us ready to sell the saltwater aquarium that I have always wanted. I don't want to run a death camp for fish though. Thanks all.