Dying leaves

ahem123

Active Member
This is a dwc grow and my plants are starting their 2nd week of 12/12 (even though they have not showed signs of flowering yet). I have not idea what this is as i cannot match it with any of the "troubleshooters". The leaves start developing black spots that eventually take over the entire leaf. It slowed down after i didn't add any nutes for a while so i suspected that it was some sort of burn, but they've been off nutes for ~2 weeks and the new top growth is still showing small potential specks.

They start like this

and end up like this


Another problem i am having, though not apparent from the camera phone pictures, is that the top leaves of the plants are turning yellow while the bottom leaves remain green.
 
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