I have 125G tank with a 40g sump. I moved a Blue (Hippo) Tang to my quarantine tank due to an Ich breakout. That was three days ago. Now several fish in the big tank have Ich and my Purple Tang is covered. It almost looks like Velvet on the Purple Tang. Do I need to add Cupramine to the entire tank? My quarantine is not big enough to house all of the fish. There are no inverts in that tank except for a few crabs and snails which I'll take out and do a fresh water dip on them. Thanks in advance for your input.