Leaves with soft spots

[freslie]

I repotted this plant 3-4 months ago using Phalaenopsis Monterey Dark Imperial Orchid Potting Mix (from Repot Me) and it has been doing well. I usually soak approximately once a week with tap water. The plant has been thriving and grown an additional leaf and has had healthy roots. For 2 weeks, using advice from another forum, I soaked with rain water. Soon after I developed problems all 3 of my orchids. This orchid has developed soft spots on 2 of its leaves. Suggestions as to what is happening?

Update: I checked the roots after soaking and they look like they have white fuzz on them. I have added 2 pictures.