hi Tassod.
i am sorry to hear the ich issue ur tank is going through. sorry for the loss as well.
One good thing is that you are about to upgrade which will give you a good chance to leave main tank fallow for min 10-12 weeks.
For now i would setup the 75 cal tank and run a HOB rated for 1.5 -2 times the volume.
i run aquaclear HOB and they make 110 i belive the biggest one for $50 rated for 110 gal.
or pick another brand that can hold the maximum amount of ceramic media you can fit in there. i have used marineland dual bio wheel hob as well in past but currently i have 2 tanks drilled and plumbed together to a single sump. (pics are on this thread in earlier pages)
Anyways you would need about 2000 grams to handle the bioload. if you cannot fit all of it in HOB then place rest in media sock and place it near powerhead or under the HOB return for maximum flow.
Run hyposalinity for minimum 4 weeks and then observe for next few more weeks.
best rule on time for hypo is to observe and keep hyposalinity till last of the ick (including from gills (unseen)) has been rid off then hold another 2-3 weeks.
here is a link to a guide on hypo.
good luck
http://www.reefcentral.com/forums/showthread.php?t=2300497