Plant dying :( pls help

Hey guys/gals,

Here's the deal : Had 6 plants, 3 turned out male, 3 female (yay). They've all had equal treatment, and recently I had a Thrip problem, little devils eating up my leaves, but I'm dealing with it and it's going ok, their numbers are getting less now.

One of the plants is in serious trouble; leaves are droopy (no overwatering), getting a dark brownish color and dying off. This is happening even on the higher leaves that haven't been touched by the thrips. When I first noticed this problem, I figured it was a nute burn (but I haven't been feeding them much, only once a week, half the recommended dosage of a 7-7-7 mix), so I flushed it... but it keeps getting worse. I read the guide on IC, and the only thing that looks similar is Potassium defficiency.

It seems that this phenomenon has spread to the other plant in the past few days. :(

If you have any ideas/suggestions I'm all ears.

Cheers for the help :jointsmile:

Additional info : They're almost 2 months old, and they've been on 12/12 for 2 weeks.

Image Description :
1st : All 3 plants
2nd : The dying plant that I flushed some days ago.
3rd : The nearby plant that shows the same symptoms on a lesser degree.
4th : The other plant that looks okay, but colors on some of the leaves look like it might begin to be in trouble as well.

Read this it may answer some questions.

http://boards.cannabis.com/grow-faqs...mping-off.html

Thanks for the input, but I don't think that's the issue.. and if it is, I don't like the part where I can't do anything about it :)

It mentions that the fungus attacks seedlings or early vegetative growth, while my plants have been on flowering for more than a week now. Then again, there weren't any pics to compare, so I don't know..

Any other ideas ?

I had a 26w CFL light (125 "real" watts) quite close to them when this happened, could that be the reason ?