What Wrong with my leaves????

whats up,

I am have a huge problem with my plants and its getting worse. If somone could please help me with this one, iwould really appreciate it. Heres the problem, as you can see. The fan leaves on the plants are getting yellow and have these brown spots with curling at the tips..whats wrong and how do I fix it??

AGE:3.5 weeks

400w MH
Temp 78 degrees
Growing medium- rockwool in claypebbles (in hydro)
humitdy 38%
PH 6.3
Nutrients ( this may be the problem,) full dosage (the plant leaves were yellow so i went from half to full)

it should be old enough for nutrients, but it looks like you may have given a smidge to much.

use fresh water next watering, and then resume with roughly 80% of the dosage.

also, i read elsewhere that the pH in hydro should be 5.7-6.2 roughly. you may consider double checking, although i doubt its the cause of your problem.

fresh water

sun spots

Yellowing of leaf tissue w/ the leaf vein remaining green- Fe chlorosis.

You may be using a nute w/ insufficient Fe, but I think it's more likely the lower availability of Fe @ higher pH. Try dropping it down to 6.0- 5.8.

Foliar feed w/ a good micronute @ about pH 5.5 should clear it up quickly.

Best I can do- can you get a pic in focus?

Brown/yellow spotting likely a Ca issue- again, try dropping yer pH.