There is no real way to get rid of ich except take all the fish out of the tank and let it sit fish less for 3-4 months, and treat the fish with hyposalinty for about a month. After that, you cannot add another fish for 6months that could carry a new strand of ick that would start the cycle all over again.
Even if you dont see the actually white spots (cysts) does not mean you dont have ich in your tank, or that fish without the spots dont have ich cuz they probably due.
I know its the last thing you want to hear but there is no medication that can scientifically kill or rid your tank of ich... TRUST ME i have tried. Your best bet to truly cure your tank is to leave it fish less and treat your fish in a QT with Copper or Hyposalinity.
I have a lot of information collected about this topic, as I have had a problem with it due to a stupid mistake on my part.
Best of luck and I hope your fish are alright!