What kind of treatment are you doing? If hyposalinity, it'll be very important to make sure your salinity stays low enough. This will require daily (or more often, depending on size of tank) fresh water top offs. It'll also be critical that you match the lowered salinity levels, when doing your water changes.
Also, when you do your water changes, siphon the bottom of the tank, as well. You'll suck up any Ich parasites that have dropped off fish and eggs they've laid.