The lower leaves on the phalaenopsis turn yellow with stains quickly

[cyclone125]

Hi! Thanks for the tips and advice.

Originally Posted by Roberta

First, welcome!

The yellow leaves are probably just old. Let it drop naturally.

I don't think that it is natural old yellowed leaves. This phalaenopsis has 7 big leaves (not counting the lateral shoot). It may be difficult to see it in the photographs, but the two bottom sheets are already almost completely yellow, and three more have begun to turn yellow with yellowed stains.
Do you think that simultaneous yellowing of 5 out of 7 leaves for several days is normal natural process?

I also had another phalaenopsis that has died within a couple of weeks with the same symptoms (completely yellow and withered).

---------- Post added at 10:53 PM ---------- Previous post was at 10:47 PM ----------

This is the link to high-resolution images to see better what is going on:

https://i.imgur.com/94i8Czx.jpg
https://i.imgur.com/sIvRfsX.jpg
https://i.imgur.com/pzfKOp4.jpg
https://i.imgur.com/QPLLPv4.jpg