why does this eep happening

[butterfly79]

I have done all the homework I can think of, I try so hard to do right with my orchids but I always have an issue.

everytime I repot my orchids in a bark mix I end up with a dead orchid within weeks.

I don't know what I do wrong. I do all the right steps, I water once a week and they go down hill. When I take a look at the issue my roots are always brown and leaves soft? I water once a week and most of the bark is dry, the bottom pieces are pretty dry as well.

Does this make sense? root rot with once a week watering? i always see a little moldy substance on the bark too or what I think is mold. Bluish/green in colour.

What am I doing that is wrong? I am at a loss. Maybe I need a medium of bark, sphag, charcoal mix?