Im not experienced but looks like Ndef to me+ over watering+rootbound.
Use a 5-10L pot straight off with some pearlite/vermiculte added to mix this will avoid root problem. I am currently on my first grow and using BioBizz nutes and canna pk13/14 which seem good so far. I havent tried any other nutes yet so i cant compare.
http://www.marijuana-seeds.net/Thanks-ThankYou.htm
Also where did the seeds come from?

Any advice i give is from a very small amount of experience please get a second oppinion.
Peace..