I'm sure I won't be much help, but fill out the complete trouble shooting form and copy it into THIS thread,
http://boards.cannabis.com/plant-pro...ing-forms.html
Maybe someone can help with more info.

30-40 day's in 1 gallon speaks of root binding,...Was there any signs of trouble when you up potted? Up pot to only 3 gallons, and I can only imagine there's more roots than soil after another 30 days. Good luck,... and it might help me answer my potential problem with my Durban Poison.

Week 8 pics are about day 56, 3 fans on one branch have started to yellow, Above and below on the same branch are still nice and green, but I'm finding yellowing leaves all over her,.... I'm not flushing yet as I was planning on running up to another 3 weeks.