Phalaenopsis with brown spots under leaves leading to yellowing and leaf death

[Jax79]

Originally Posted by Dimples

North facing window could be too low light depending on what’s outside. If they’re not getting enough light for extended periods, they’ll have to sacrifice older leaves when they grow new ones.

This isn’t normal, oldest leaf drop, it’s on all of the leaves as you can see in the pictures. And again, these plants have been in this window for over 5 years, and they bloom twice a year and have great roots, so light definitely isn’t the problem. Thanks anyway.