This often precedes a leaf dying and falling off. If growing conditions are otherwise good the plant will make more leaves.
The medium looks good. How long have you had it? What are your day/night temperatures? Humidity? What kind of light is it getting? How are you watering? When was it repotted?
__________________ May the bridges I've burned light my way.
I've had it about a year and a half. I learned it had bad root rot about 6 months in. I read how to care for it and repotted it about a year ago. Since then I can see new roots slowly growing and new leaves. My night temps are around 66, daytime 68, low humidity. We live in the north. It gets indirect light. I water it heavily when dry, and let it all drain off in the sink.
With low humidity and cooler temperatures Phals carry fewer leaves than they do with warm, humid conditions. Many carry about 3-4 leaves inside a house. Has it rebloomed for you? How are you determining when it's time to water? It's better if they don't get bone dry throughout the pot.
I would add more medium to the pot, so medium comes up to the base of the leaves on the stem. Developing roots will have a better chance to grow than if exposed to low humidity air.
__________________ May the bridges I've burned light my way.
Thank you for the advise on watering and adding more medium. I'll do those things. It has not rebloomed . It has 5 leaves, though one is dying. The leaves are on the small side.
My best guess about not reblooming and having small leaves is insufficient watering. I doubt the medium is bad after only a year. From the look of it it's getting plenty of light. Too much light can cause small, purplish leaves, but you said it gets indirect light.
Try watering a day or two earlier than you do now. If you aren't fertilizing, try to add that about once a week during warm weather and once a month in winter.
__________________ May the bridges I've burned light my way.