I have just used this treatment recently.
I was going to get the other King British treatment as that is what I had been using, have to say with no luck.
I treated the tank on the next due treatment day with the WS3 and then again for a second treatment and now the signs of white spot have gone. No flicking anymore from my loaches no spots on the fish that had them. I am still treating the tank for a couple more treatments to make sure that this horrible parasite has gone. This treatment worked for me.
I myself would not put it in a hospital tank because it is likely that if one fish has ich then some of the others will also have it, in my experience and having asked questions myself on this forum about the same issue, going by the advice I was given, leave it in the main tank and treat all the fish
Tropjunky, please don't think I am disagreeing with your advice on this one by the way I am just giving my experience on this treatment, there may be other treatments on the market such as the one which Tropjunky has recommended but this one has worked for me so I would recommend it.
Good luck in getting rid of the ich KF.
Kaz