Yellow Spots on Vanda leaves

[birdwomn]

I got some Vandas from a reputable Vanda seller about 5 weeks ago and two of them recently developed yellow spots on the lower leaves.

I noticed the yellow spots yesterday. This morning both of them have a yellow leaf with a black spot on the underside.

I have read all the old threads on this topic and have the Motes book (not the new one on just Vandas, the growing orchids in Florida one).

Since I am new to this, I thought I would check and see what treatment is recommended by those with more experience.

I apologize for the very blurry photo of the underside of the leaves with the black spots.