Light green spots on phal leaves

[cutie_monster]

hello fellow orchid lovers! can someone help me with my rescue phal? i found this little guy on the clearance rack about 8 months ago all shriveled up & with root rot. well, i nursed it back to health and for a long time its been doing great. it grew lots of new roots, 2 new leaves, and even put out a spike and bloomed 5 flowers.
these spots started some time this past week (the spots weren't there when i watered last friday)...


Untitled by big_cutie_monster, on Flickr


Untitled by big_cutie_monster, on Flickr


Untitled by big_cutie_monster, on Flickr


Untitled by big_cutie_monster, on Flickr

this phal sits in a north-east window and gets about 30-45 minutes of morning sunlight then bright but indirect light the rest of the day. it is potted in better gro orchid bark phaleanopsis mix. potted up about 8 months ago after brought home from store. i water every 7-9 days as needed & usually feed immediately after watering. i water it by flushing the pot with temperate water, then i use a small peice of paper
towel to dry the leaves and crown area. also, this plant along with 2 others live in my bedroom & i run a fan at night,'so they get plent of air circ. additionally, none of the other 3 phals in my home are having these symptoms and one of them sits only inches away from this one. in fact, none of the other phals that have ever lived in my home have ever been sick. any advice is greatly appreciated. thanks.