Be sure to keep treating with medications at full dose for many more days. You have not completely eliminated every single ich organism in just 3 days. Ich's natural life cycle is 3 to 4 days anyway, and it is only vulnerable for a few hours during those days. So, you have to make sure that there is ample medication available to continuously kill the ich organisms as they transition into that vulnerable-to-medication stage. I would personally recommend 7 to 10 addiitonal days. That way, you can completely kill off each and every single ich organism, and it ich won't come back.