Black spots on vanda roots.

[Justright1]

Hello. I'm struggling with some Vandas. I own about two vanda orchids. I follow the regular care for Vanda orchids. I own a 2 gallon bucket full of water and dip them everyday. My watering is kind of strange sometimes I let one of them sit in the bucket for 3 hours and then maybe the next one for 1 hour. I'm quite busy in the day so I never really have a timer on them. I'm just realizing there are black spots on the old roots , and have this strange pink pigment to them. I just thought that the black spots were something on the old roots , but now they are traveling to the new root growth. I noticed one time that I haven't changed the bucket in a while, and when I dipped the orchid in I realized the water had a strange film on top of it. I have a feeling dipping the orchids in that strange film a couple times led to this strange black spotting. I don't know what it is, and is there any way to get it off or prevent it from spreading? And is my orchids going to die?