Use caution with the prescribed time frames. C. irritans has a life cycle and it doesn't always conform to a window of time. I will usually keep the fish in hyposaline conditions for at least another full week, even after all symptoms have ceased to be visible for three weeks. I've had recurrences of the parasite during this extra week, and then had to start the procedure all over. After the salinity is raised to display tank levels, another week in quarantine is a safe practice. If after this time passes and the fish are doing well, they can be placed back in the main tank. Impatience during this or any medical intervention can be a major setback so don't rush things just to get your fish back into the main tank.