Help! Losing fish fast!

I am need of help, I think.
First, the problem.
I picked up ich the last time I added fish to my tank. Nothing I can do to change what should have been done. Needless to say, I didn't have a hospital tank set-up and it took me a bit to get one set up. I tied the 135gal main to my new 50gal hospital tank and let them equalize for 24 hours. Then I transferred my fish to the hospital tank and disconnected the two tanks before treating the water. I had already lost one fish in the display tank to the disease and one more was in pretty bad shape when I moved them over. Therefore, I tried a fresh-water dip on the one bad fish and it didn't work, I lost it within 8 hours.
I treated the tank with coppersafe and maracide first off then added a dose of Rid-Ich+ about 12 hours later. Day two, I did a 10% water change to lower the salinity a bit and gave a second dose of the Rid-Ich+ as directed. Day three, I lost two more fish and another one is in really bad shape, two others are steadily going down hill. I did a 25% water change and gave the three damaged fish a 3 minute 1.009 water dip. Salinity in tank is now 1.016.
I am ceasing treatment with the Rid-Ich+ at this point. One of the three fish is on its last breath, one is inactive and breathing rapidly, and the third is active but breathing rapidly. I have five other fish that all seem to be doing fine and have shown no signs of distress or spots.
My tank parameters are all good, 0 ammonia, 0 nitrates, 0 nitrites, 0 phosphates, 8.4 pH, 81 degrees, 1.016 sg, 50 gal hospital with 10 gal sump running at 600gph, 2 seaclone 100 protein skimmers.
I am pretty sure I am at the point where I need to sit and wait, but I hate just watching the sick ones die without doing more. I am regretting using the Rid-Ich+ at this point, but was hoping for some faster relief than the copper could provide for the ultra sick fish.
The three sickest fish are all tangs, one blue, one scopas, and one yellow (scopas won't be alive more than another hour or two at the most though).

 

Thanks Craig, I'll try a bit of garlic. What SG causes the least stress during this period in the hospital tank? Like I said, I am currently at 1.016, but I have read that going lower is better for the fish and hard on the ich too. I want to make the water conditions as easy on their respiratory systems as possible. Also, should I do some antibacterial treatment as a preventative measure for secondary infections, or is that risking more stress on their systems?
Will
(not in a very good mood today)

 

I am leaving the tank alone for the time being and the parameters are holding constant. The scopas tang seems to be doing much better today and looks more healthy. My yellow tang seems to be struggling a bit more today than yesterday however. All three tangs I have are covered heavily in white spots more so than before. I do have coppersafe in the tank and will continue to monitor the tank parameters to keep them constant.
I am taking advantage of the time my display tank is without fish and am adding a couple of things to it. I figure 6-8 weeks should be a good time to get some new corals, anenomies, and inverts for the main display tank.
Thanks for the advice everyone.