I have 9 phals (I know that's nothing). They are all blooming and
they have all bloomed 4 or 5 times before. I water them with
fertilized water once a week and they have thrived.

All of a sudden two of them are losing their blooms. The flowers are
dying from the newest to the oldest so I know for sure there's a
problem. The plants are otherwise very healthy and are growing new
leaves. They don't look like they need to be repotted.

I always change the potting medium when they finish blooming so I
don't think that's the problem either.

Nothing has changed that I can think of. The other plants are fine so
far.

Any ideas?

thanks

Jane