When I treat my tanks with salt, I use API Aquarium salt, 2tsp per gallon and dissolve it(completely) in about a gallon of tank water and add it very slowly, a little at a time, about a quarter of it every half hr to an hour, keeping an eye on how my fish are reacting. It is the salt that kills the Ich Tomont. I even add another HOB filter or power head to make it easier on the fish, as well. Make sure you do it for at least 7 days to make sure to kill all of them because they attach themselves to inanimate objects as well and when the fish rub against it, voila, a new host. I hope he's feeling better. Keep a close eye on your water parameters as well,. Good luck!!!
ps...I have 3 Clown Loaches and 2 YoYo loaches and they all do well with the salt treatment.