small seedling burn

hey ,
i need your help....
this are pix of two california orange bud plants which dont look so good. #2 was planted few days later....
they are in the best potting soil i could get, water ph 6.5 (allso run off water check) water ec is 0.3 and i dont think i over water them, no nuts in water , only a\c water mixed with little tap water, so i think i do every thing right. it is even stranger since i have two other jock horror plants that looks verry healthy with no problems at all. allso, they get alot of cfl's light ,so i dont think this is the issue. i'm a new grower and this are my first plants.
hope to get some ideas about this problem, you can see they pale green , week , and the older one have this burnt tips....
thanx in advance,
eezee.