Vanda in vase: problem & buds!

[Buds!]

Hi everyone,
Yes, I am still growing my vandas in vases. I purchased 3 vandas in May.
I need some help from the vanda experts because I don't know what I am doing wrong?

The Results:

Vanda Sansai Blue
This Vanda came with some strange blotches on the leaves, some of the bottom leaves were also yellow. After 3 months in my care, it has grown LOTS of new roots. The problem is that I don't understand why the lower leaves are turning yellow and dropping off.
I have lost 3 leaves and another one/ two is going to drop soon.
The Sansai Blue gets the same care as the other two vandas: water/ soak everyday (or every second day, depending on weather), and fertilize weekly.
This Sansai Blue also had a soak in Epson salt five weeks ago. I am not sure if that helped?
I wonder if my Sansai Blue came sick? Or am I doing something wrong?




Princess Mikasa Blue & Vanda Blue Magic
These two just took off and I am going to get some flowers soon. I couldn't be happier!





As you can see this is quite confusing for me, the two vandas above are very healthy, I am not sure what is happening with the Sansai Blue?

Youe help would be most appreciated!
Juliet