phalaenopsis bellina yellow leaves

[aaaeeerrr]

i have a phalaenopsis bellina that i bougth from ebay last year maybe in summer months and it was doing well it even put out a new leaf but a few weeks ago the leaves started to turn yellow and i dont know why

i had it in Pinus pinaster bark that i collected myself it had a veryyyyy good air circulation but when i saw the leaves turning yellow i bought orchid mix and repot it the roots are green and healthy it had one or two dead roots that i´ve cut of besides that i cant see nothing wrong

here some pics

the small leaf was the one that grew after i got it in the mail