Treatment for mycelium on Phal Poots and Drying Bud Question

[czygyny]

I recently repotted a Phal with fresh bark. After about a month I was horrified to see tiny white pinpricks of mushroom mycelium all over the roots and around in the medium.

I rinsed the roots thoroughly and soaked the bottom of the plant in a mild solution of baking soda for a few minutes and tossed out the bark and started over.

Is there a standard procedure for treatment, either chemical or household preparations, that I can consider if this happens again?

Also, my first-ever Phal was obtained decades ago and it bloomed and stayed healthy for many years. It eventually would not hold the buds to opening, but they would wither and die. Nothing I did helped and I finally discarded the plant.

What could have happened to it since I had been so successful up to that point? None of my present orchids do this, other than my Miltonia, which never does well.