Oh, I didn't have the ich. It's still unclear what killed the 6 fish and left the others alive. I had no spots or rubbing, justone day they would hide and not eat the next day instant death.
I did let my tank stay as is without adding anything for about 2 months to be safe in case it was velvet.
I know a bit about the ich, and if you put your fish into a qt tank and medicate, THEN leave the tank fallow for 6-8 weeks the ich will be dead. It doesnt host onto inverts or corals only fish. So remove the fish and they can't live. I think the full life cycle of ich is 6 weeks but people are usually a little cautious and add some time.
You can treat in a qt with copper like cupramine or you can use the hypo salinity method in which you lower your salinity each day by a little bit to get the ich to dislodge off the fish.
here's a link for you
Marine Ich or White Spot Disease
I hope you beat this thing!! Let me know what you decide to do. I'm rooting for ya!