Help! Is this root rot?

[Mountaineer370]

That's definitely a Phalaenopsis that you have there, and it looks pretty happy and healthy to me. In many of my older Phals that have roots visible at the top of the potting medium as shown in your picture, the exposed part of the root will turn more brown with age and develop a somewhat woody texture. I believe it's due in large part to the low humidity in my home (as mentioned by estacion seca). None of the roots that I'm seeing in your pics should be cut.

Ditto to the watering advice given by everyone so far. I'm assuming here that there are holes in the bottom of that pot for proper drainage. If not, that needs to be corrected soon. With holes, the quarter-cup once a week doesn't seem like enough with your loose, chunky medium, and if you either soak it for a while or flush a good amount of water through the pot, you'll give those top roots a chance to take in some moisture.

Also, it's my own habit, when I water, to have a spray bottle handy, and I will give a good spray to any exposed roots that didn't happen to get wet in the watering.