I'm not sure if you're asking how long you should soak your foot or how long you should keep up with this home remedy. So I'll try to answer both.
At first I'd only soak my foot for a few minutes since it will probably sting a bit. As you get use to the process and your foot starts to heal you can start soaking a little longer but I really wouldn't soak longer than 10 minutes at a time.
For some people this home remedy seems to work very fast and for others it takes awhile longer. I'm sure a lot depends on how long you have been dealing with the fungus and Athletes foot and of course how severe it has developed to. I know of some people that will use this remedy for a couple of months before the problem is completely gone. So I'd suggest that even when you see results and your foot is healing nicely it won't hurt to soak once a week for a while longer just to make sure the fungus has been distroyed.
