It is true that daily water changes might remove some of the parasites, but I have never done this. Water changes on fish that are already under severe stress (which is why they caught ich) will unsettle them somewhat, and when no real purpose is achieved it doesn't seem wise. If the temperature in the tank water is 86F (or a tad higher), this kills the free swimming stage. It is always possible that the odd one might get through this, but the chances of removing the "odd one" with daily water changes is minimal at best. Give the fish some rest, they will be able to build their immune systems and fight this off better.
A substantial water change of 70-75% of the tank water should be done when you start the 2-week treatment, and you can increase the temperature of the fresh water to get the temperature higher. Depending what the normal (present) water temperature is, you can raise it a few degrees. Turn the heater up so it completes the job. Increase surface disturbance so there is a good gas exchange bringing more oxygen in to the warmer water.
Another water change of 60-70% one week later. At the end of the second week, or close to it, turn the heater back to normal and let the tank water temperature lower naturally. Continue water changes after the end of the second week normally.
