1. If I'm not mistaken, that meter is reading 35% humidity. Should it really be 35% humidity, that is really low for a Phal to tolerate well. Shoot for at least 50%.
2. Watering once a week is usually not adequate for many orchids. If you want a recommendation for orchids you can water once or twice a week I can do so, but it'll be an orchid in a genus you've probably never heard of at the moment.
3. I generally don't recommend cutting living roots off of Phals. They can get super touchy about having their roots messed with. Phals also have this wonderful ability where if they lose all of their leaves, but a large number of roots are still alive, the orchid can still bounce back and grow entirely new leaves to replace every single leaf that fell off. I've seen it happen multiple times on the Phals I grow, and I can prove it with photos or videos, over-and-over again with multiple different kinds of Phalaenopsis, species or hybrid - it doesn't matter. I no longer freak out when my Phals drop leaves, but their roots are still alive and doing well, like I used to when I was new to the hobby.
So to put you at ease, your Phalaenopsis can easily recover, you just have to learn how to treat the Phal right.
---------- Post added at 08:44 PM ---------- Previous post was at 08:39 PM ----------
Oh, and welcome to the OB, btw.
---------- Post added at 08:46 PM ---------- Previous post was at 08:44 PM ----------
One more thing, I'd be careful about rinsing roots with hydrogen peroxide next time, it might cause damage.
Just a reminder, I highly recommend not sitting the orchid's pot in standing water for more than a couple hours.