Hi devic and welcome to the forum.
How many discus do you have and how old are they?
When did you introduce them in to your tank ? Did they get sick right away from the start?
Are you sure its ich and not just discus pimples from a bad water quallity?
I would start with quarantining the sick discus in a QT tank and change +80% water daily along with poop siphoning, filter cleaning and regular glass wiping.
See how it goes for a week or two and than proceed with medications only if needed.
Most of the health problems discus have are usually related with not sufficient water quallity and most of them can be solved with just lots of clean and fresh water .
In meanwhile start reading the stickies in the begginer section for proper discus keeping and watch the video from the stickies .
Good luck Devic.