white mold on roots and moss of 2 mini Phalaenopsis and a Neofinetia

[WhiteRabbit]

You can also soak with hydrogen peroxide 3%.

Your Phal may be dropping leaves due to root problems. When you say your plants are dry before watering - how are you judging that? Sphag will be dry on top and still quite moist or even wet further down and in the center.

High humidity with lack of air circulation can also lead to mold/ fungus.