First time grower, first time problem...any help is greatly apprichiated, thanks

There only about a month old now and this is the 1st time anything has really gone wrong. Im really trying to finish these with the least amount of problems and stress as possible. I have 1 1000w hps,a well ventilated room, all in 3g pots. I've been watering every other day or so, and have been using ferts, while keeping the ph between 6.9-7. I was thinking this was a nitrogen diff or maybe sulfur but am unsure really. Anyone able to pinpoint the problem? I checked them last night and they were perfect, it wasnt until the light came on today that i saw this.

Again, any help is greatly apprichiated

Looks like a nutrient deficiency or toxicity. I'm too high to figure put specifically which one, hopefully this points you in a better direction.

I've got a plant doing kind of the same thing. The new growth is a little yellow on the tips. Old growth looks good. All my other 7 plants look great. Best I could come up with in my case was a zinc deficiency. I'm just gonna wait it out. In your case, if it's just that one leaf or two and it isn't spreading, maybe it's something isolated to that leaf.

look at the other leaves, no problem, I think its just a retarded leaf. pick it like a scab and see what happens.

Whether you have too much or too few of any nutes, the solution is the same. Flush with low ppm water and feed lightly. Also, test the ppm and PH of your drainage water.

wow, thanks severyone for the speedy response. I think il have to use this forum more often..alot of great info here. I flushed it last night just in case that would work and have yet to check today, but the runoff water was 6.9. I guess if that doesnt work out i will just pick it off. Im just a little worried it will shock the plant and possibly cause hermie from stress. That logical?