I would be concerned about the leaves on both plants. The plant with the striped leaves has ring spots. Sometimes that can be fungal, but often it is viral. Viruses are eventually fatal to the plant. The only way you can be sure if it is a virus (if the plant is important to you) is to do testing to determine if it is virus, or not. A lab called Critter Creek, and some others, can do the testing. Viruses can't be treated; the only way to prevent spread to other orchids is to destroy the plant & discard it in the trash. Sorry.
The one in the back (no stripes) seems more likely to be fungal. Possibly Anthracnose? Treat with a fungicide that will work on that problem.
Here is a link to information on orchid pests and diseases, including guides for selecting chemicals to treat fungal diseases and other problems:
http://www.phelpsfarm.com/OrchidPestsandDiseases.pdf
Good luck!