This. Right here. The only true cure for ich is to go fallow, otherwise it will always be in your system. With the parasite in your tank you can think of it like the common cold, and a healthy fish will fight it off quickly. Ginger and garlic are supposed to be good to stimulate appetite and vit c boosts the immune system. Antibiotics are really pointless because it is a parasite not a bacterial infection, think about it, would you give a kid amoxacillan to cure lice? The only true options are to starve it out by going fallow for a few months or let the fish fight it off naturally. But as soon as your fish gets stressed be ready for an outbreak.
Ps. Use a Uv sterylizer to kill the tomites. I think it may lower you population of pods and good bacteria but it will kill tomites and algae stuffs.