Phal leaves firm but slowly yellowing

[Catriona]

Fiacre, thank you so much for your response. The orchid looked worse in the photos than in real life - leaves were all very firm despite discolouration, which was actually quite a slow process. However, obviously something wrong, crown rot was diagnosed by a couple of people on another forum. So I sliced (v. painful for me, if not the plant) and peroxided and cinnamon-ed. The roots looked quite good, and there were 2 perfect leaves. Re-potted in new bark & the orchid's dealt with all the trauma fairly well - it's hanging in there.
Again, thanks for your consideration.
Regards.

[Fiacre]

I'm glad that your phal has been properly diagnosed and treated, Catriona! It's never fun to perform emergency surgery on an orchid, but they can take a lot of abuse.

Here's to some happy growing in the future!