Problems with Spath

Hi! I had this posted on a different forum and it was suggested you may be able to help. :)

The plant has lots of healthy white roots and flowers arriving, perky leaves and, well, spots. It belongs to a friend of mine and currently I have it to see if we can get it green again with the help of DG folks. It went from a medium light location to a brighter spot, no direct sun, and this started. First one or two leaves then gradually the whole thing. I've tried feeding it with Miracle Grow general fertilizer in a weak solution with no results.
Right now I'm trying Epsom salt as recommended on the other forum. I've gotten to the point where I'm not sure if it's working or not LOL! "Hmmm, I THINK I see some improvement...maybe?" It sure hasn't gone back to healthy green though.

It's been nicknamed a rare form of Leopard spath for the time being. Any suggestions on how to green this baby up would be appreciated.

Another pic.

Ican, is in kept inside or outside? If inside could it now be in a draft from fan or AC?

No unfortunately it isn't a draft situation. It is inside but not near a vent. It was in a medium light room and it was moved into brighter light before this started but I'm not sure if that's part of the problem. My original guess was a deficiency of some kind but feeding it hasn't changed anything.

Sometimes chlorosis indicates an iron deficiency....mayhap give it some liquid chelated iron?

I'm willing to try! :) Thanks!