Your orchids look pretty good to me. The few spots on your vanda leaves are probably a leaf spotting fungus. Those don't kill the plants but they look unsightly and the spot will never go away of course. Oncidiums are especially prone to leaf spotting fungus. I use a fungicide on my vandas and oncidiums about once every two months. Diathane alone or in combination with Thyomil (not sure of the spelling) works well. Some people use BanRot or Cleary's. If you don't treat it, you'll get some more spots but it won't kill the plant.
You might try switching to whole milk instead of skim.
Seriously, it's hard to tell from photos, but the gram looks like spider mite damage. I use the Bayer Advanced 3in1 with miticide with good results.
Spots on Vandas are a common issue - you can go ahead and try the fungicide or the Bayer 3-1 (one of the '3' is a fungicide), but it's not that big a deal.