Actualy, you know what i think it was..

..the guy came around to fix my comp, so i flicked the switch on my growroom..thing is, i forgot to flick it back on again, so they were without light for over 24 hrs.
I know that in the past, if the lights have blown..undetected for a few days..the lack of photosynthesis turns them pale after a day or two.

I wouldnt have thought that 24 hours darkness would have affected them much, but the pics speak for themselves..and i hav'nt icreased the nute level yet..im going to though, coz they still look a bit anaemic to me.