I want to chime in, I have a 240 reef. I set this tank up and wanted to have an achillies as my centerpiece fish. I live in a 850sqft house so the 240 takes up half the house.....so talking the wife into a 75 for a QT is totally out of the question. I had a 90 reef for quite some time and was going to move quite a bit of stuff from it to the new 240. I ordered him and a chevron through live aquaria since they have the guarante. Got the fish in and they looked great. I had a 5-6 inch....aggressive purple in the 90. I let the 2 tangs get settled for about a month then added the purple. The two flopped around the first day, then after acted like neither existed. All and all, had the achillies about 4 months. It would get ich, time after time. Worse and worst each time. I fed 3 times a day, garlic and welcome soaked food. He ate like a pig till the day he died. I really varied his diet....frozen, flake, pellet, nori....you name it. I since have had 2 others. All the same. Each time waiting 3 months in between. Typically lose a few others at the same time. No achillies in the tank, no ich.....at least not visible.....the second I put an achillies.....there is the ich. I have one now. He has fought the ich once so far and looks great today. He is 2 months old now.....we will see. I really hope he works out. I should have added, I keep salinity at 1.023 and have never had detectable nitrates.....ever. I run a super low nutrient tank. I also forgot to add that each time now the other tangs are in there, I use egg crate and block 1/3 of the tank to acclimate the fish then after some time I remove it