Plant problem - around 2 1/2 weeks old

Hi,
I have a plant that is in its 3rd week, and up until about 5 days ago, was looking perfectly healthy. Around that time, i noticed a couple of small grey spots appeared on the oldest leaves just before i went to bed. The next day, there were more of the spots, and they went from having a small, almost 'drawn on with a pencil' grey color, to bigger and browner. Now this necrotic tissue covers half the oldest leaves and they have turned a yellow (game over for sure for those leaves). I kept watching the plant to see if the spots would appear anywhere else, and today i noticed the second oldest leaves now have a couple of the pencil-grey faint small markings, and i know how this will turn out now. anyone help me?! its game over for this formerly healthy plant if i cant fix the problem in a couple of days. using coco, ph neutral water, no nutes, fluoros, lights about 2 1/2 inches from the plants. heat between 19 and 24 degrees celsius, hum between 40 and 60 percent.

this is really tripping me out, ive looked through SO many pics of sick plants and nothing seems to match the description. The pencil-grey spots seem really out of the ordinary.

please only reply to this post if you have a fair idea (over 50 percent) of what might be the problem. noobs like me thinking out loud on this thread isnt going to help anyone


thanks in advance for your time

shit, how do i post pics? i really am a newb

click on the reply button, than scroll down a lil bit till you see manage attachments button.click on it and browse your pics.than click the upload button and voila - pics are uploaded

here we go, pic time

what type of soil man? is it pre-nuted?

take a look @ this - International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles! !!! hope that helps ya. Cheers!!! CheetaH

thanks for the link mate but i've been all through the guide about 10 times, and all thru ic mag's infirmary too. i wouldnt have come here without having a good research first. the thing about it that seems unique is the grey spots appearing randomly on sequentially younger leaves. seriouisly looks like i got a grey lead and drew them on at first. this is before they turn nasty, and can take some days at the grey stage before the spots necrotise... oh an cheetah - its non nuted coco mix as stated above

this is killing me!

they need nutes man.... i'm over 50% sure