Here's a copy of how I use Cupramine. Also, ALL the fish in your tank now have ich; the tank has it, not just the fish you see with spots. You need to find a way to QT?HT all of your fish while your DT stays fishless for 12 weeks or so. When this is over, use a good QT regemin on all new fish and never go through this again. BTW; your comments on LFS advice are absolutely right. Too bad, they used to be a good source of info.
"I really like Cupramine and use it with all new fish; have for years. I like a softer approach to Cupramine, here it is. I use Cupramine at about .35-.40 pmm, lower than the bottle directions of .5ppm. I also take several days to go from 0 to .35-.40, not the 3 days SeaChem suggests. Also, be sure fish are eating in the QT before adding any Cu; loss of appetite is a 1st sign of copper intolerance. If a fish seems to be having CU problems (this is rare); remove Cu ASAP and let the fish recover and start over. Of course, in an emergency, all of this is out the window. SeaChem (Mfg. of Cupramine) is fine with this procedure and has said they will change labeling, but who knows when. SeaChem has excellent tech support: 1-888-seachem, I think). Here's everything you need to know about Cupramine, the FAQ are great;
http://www.seachem.com/Products/prod...Cupramine.html
I've used Cupramine, using this procedure on more fish than most folks would believe, Enough to stock about 1000 gals of DTs before and after Katrina, and fish from other sources) and haven't seen ich in any of my DTs in many years."