dendrobium leaf discoloration (yellowing, spots, dropped leaves)
 

:hello
I'm somewhat new to the orchid hobby, and after a good number of phal rescues I branched out and bought my first dendrobium a few weeks ago.

Pretty blooms, a few baby canes; I thought I'd chosen a healthy plant until a few days passed and the blooms on the third spike started to pale and develop softer brown spots on them.

Pictures:
Remaining infected leaf; the yellow seemed to start gradually in sort of a blotchy pattern, taking over the leaf. The brown spot at the tip is softer than the rest of the leaf.

ht tp: //i.img ur. com/9AvsEh3.png Infected cane(?)/leaf with trimmed third spike.

ht tp ://i.im gur .com/5iVloCt.png Detail
h ttp ://i.im gur. com/C8U7RS3.png Underside
ht tp ://i.im gur. com/5Q9wWfC.png Spots on the cane sheaths. This cane was cut when I bought the plant.

ht tp: //i.im gur. co m/Xu8xJl9.png This spot is on a healthy spike and has yet to cause any noticable damage, but I have no idea what it is-
ht tp ://i.im gur. co m/ezXQr39.png A different cane from above, the tips of the top two leaves are yellow. Is this an effect from a cold draft, or, god forbid, whatever is going on with the other cane?:(

Thanks for any insights!! ID is also appreciated :blushing:
I can't figure out how to get pictures to show up in the post; neither bbc code or html will work I'm sorry :dumb:

I'm using tapatalk right now, so can't get to the photo links (btw, http://www.orchidboard.com/community...ng-photos.html here) - but the one posted photo, the soft dark spot on leaf tip is some kind of rot I think - maybe from water on leaf during low temps :dunno:

So, what temps has this been getting? How often are you watering? What is the potting media?