Yellowing leaves after transplant

[littleflower]

Help! I bought a cymbidium from the grocery store, it was thriving on my screened porch, lots of new growth. However, it was very very crowded in the pot, so I very carefully transplanted it, and divided it into two. That was about six weeks ago, and since then, I’ve had leaves that turn yellow, then almost reddish, and die. I haven’t changed the location of the plant(s) or the watering schedule (Weekly with distilled water), I allow them to thoroughly drain. When I transplanted, I used an orchid bark mix. Thoughts and/or suggestions?