Root Problem

[orchid-eric]

Something is up with some of my roots. They grow very well. Nice and plump, bright white with green tips. Then on some, the root tips die. They turn black and the root starts to die. Sometimes the whole root and other times just a little of it. This happens with different genera not just one. There's nothing wrong with the orchid plants themselves. I've wondered if it was my water. I live in the country so we have well water. It's very soft and has a ph of 7.0. I don't remember having this problem when I lived in the city. What do you think?
Thanks!