Hi Chickita and welcome to the forum!
First off if you could please goto your profile and update your profile location. We have members across the world and different locations = different advice.
Pics would be great for this, but I also think that you are doing a few things incorrectly. One is underwatering. Phals like their medium slightly damp before the next watering. They don't like to dry out completely. Another is misting at night. This can pose a potential threat of crown rot. Third is the lack of air flow to the plant. Just a door opening every now and then isn't sufficient enough. Phals like constant airflow that is light. This prevents rot and fungus from growing on the plant.
A pic of your plant is highly suggested so we can see what is going on. As for the yellowing of the leaves it could be natural courses of the older leaves dying off, but then again, it could be something else.