Please help identify my problem.. PICTURES INCLUDED.

100% perlite? I not no hydro grower, it don't look burnt
how many ppm you feeding it could be under fed or over
watering too often how the roots look or can you even check'em
you could included a whole plant pic to get the over all feel for the plant~

No, its 90% hydroton. I just topped it with perlite to make it harder for pests to reach my rockwool.
I was getting about 1000ppm, now its getting 750ppm. Its flooding/draining for 15mins every 4 hours.
The roots are fine, because i just planted these into their buckets a week ago.
The pics show basically the whole plant because they only have their first 1 or 2 sets of leaves.

Anyway, i dont think im UNDER watering, because they're so small, but who knows.
Im thinking it could be nute burn. I just dont know.

Can somebody PLEASE tell me what this looks like?

Might be too much water/food. I had a similar problem with some Woody Kush. Leaves were sustaining damage similar to yours. Read about my problem and what fixed it here: Overfeed or Underfeed - Fan Leaf Problems

If you're using a rockwool block to start your plants be sure to set the block above the waterline in your buckets to avoid over-soaking them. Ebb-N-Flows work great, especially if you get the newer style buckets that do not retain an inch or so of water after draining. Also try dropping your PPM's much lower, say 450-600 max in first week of veg, gradually moving up to 1000-1400 in mid to late flower.

Good luck!

read Guide to Nutrient Deficiency or Toxicity

what is your nutrient PH? in your first picture the "cupping" ive seen that in a soil grow right before they began to show the twisted leave symptoms of a ph problem in my case a soil ph meter did reveal a need to adjust soil. as far as the discoloration i don't really do that much hydro but in my opinion the size those are 15 min sessions of flood and drain 6 times a day is to much for those unless they had massive (EZ clone type) root systems at transplant. Rockwool will hold quite a bit of water. So what size rockwool are you using and what is the temp of your nutrient solution if your room/space is getting that warm?

I would say it is over watering. I water my plants ,flood and drain, in hydroton 3 times a day in 3 minute intervals. I am using gh flora 3 part plus floracious and kool bloom.DSCN1596.jpgDSCN1605.jpgDSCN1606.jpg

I think you guys are right, it might be over-watering and/or too much ppm.

Right now my guardian meter reads as follows: 700 ppm, 70 degrees f, and 6.0 ph.
Which i think SHOULD be fine, but maybe ill lower the ppm's a bit more, and lessen the watering.

Because of root aphids on my last grow (which got destroyed and i had to restart with this one) i buried
the rockwool a tiny bit deeper than usual, so probably about half the cube gets wet.. its a 2x2 or 3x3 cube.

Anyway, i think ill top the res with some plain filtered water to lower the ppms, and dial back the watering
to like every 6 hours or something, and hopefully that will help. However 15 minute interval is the lowest im
able to set the dial, so i cant go any lower than that. However it takes a while to fill anyhow so realistically its
not actually fully filled for very long even at that setting.

Thanks for all the feedback guys, i really appreciate it.
Anybody else care to chime in? i'd still love to hear what you think.

yeah i would say ur ppm is insane for those baby plants but everyone already did