problem with leaves?

I,ve noticed a few probs with the leafs on my nl plants , they're about 2 weeks into flowering under 125w cfl, can anybody tell me what they think the prob might be ,the two pics are on the most severley damaged leaves ,the rest of the leafs seem ok apart from the tips beginning to dry a little,

too much nutes the burn on the tips is a good indicator of this which one i cant tell from the pics flush for a while then start feeding again. little less than before should be o.k

after another look at the pics could be nitrogen o.d they are very dark green

yea i originally had them potted in mg soil with nutrients in em (haven't given them any nutes apart from that) and one of em started to nute burn pretty bad ,I keep flushing the soil but the burn seems to keep spreading, how much water should i flush through and how often?

that is pretty strange can you clarify on what type of compost you used and you say you have not fed. have you checked water p.h as sometimes this can trigger nute probs and also check e.c value if your using tap water it can have a lot of things dissolved into it. o and just to make things more complicated tap water can change day to day.