Take the advice of those who know, especially those who have lived through it ... (previous posts)
There is no quick fix for ICH

so stop trying to fix it quickly
Some live with it, and some are devastated by it
I don't care what others say about this med and that med
There's no 'fix' for Cryptocaryon irritans
You'll get 100s of answers from dozens of peeps who have used 'product' that has worked for them
In the meantime, are you going to risk your fish ?
They will just as easily die while you try feeding them garlic or whatever
So, first, your fish are infected
You may lose some
This is reefkeeping, so get used to it
Get a QT and use it for at least your new fish
If your tank is infected and you want to completely remove it forever, move the fish to a QT and leave the main tank fallow for 9+ weeks
Then, in the future, QT everything
Keep feeding the Display for the fallow period to keep the corals/shrimps/crabs and such alive
Don't hurt your fish in the QT with copper, but rather consider hyposalinity
Don't rush putting your fish back in the DT as it takes up to 8-9 weeks for Ich to die off (in most cases)
Umm, don't know what else to say ...
Anyone else ?
And for anyone interested, read this about the
myths of Marine Ich