plant looks sick...help

Ok everybody so my plant started looking sick, so naturally i started trying to take better care of her. I tried everything i know of to help and she still looks like this, so i came to ask the more experienced...any advice??

looks like some wicked heat stress there

looks like nute burn. Flush well and feed at 1/4 to 1/2 strength after.

what soil are you using and what nutes and feeding schedule?

It's not heat stress. The hottest its ever gotten in there was 79F, but it stays around 75F. Plus, i have 3 others that are loving life.
I water once every three to four days. i stick my finger in the soil about an inch down to see if its dry or not. Im using coco husk and flora series nutes. i went from 1/2 strength to 1/4 and that didn't fix the problem, cuz i thought it was nute burn to. I just found this picture, you think it could be a zinc deficiency?




View attachment 2185884

can you check the PPM of your run off water?

It's nute burn. The leaves are yellowing and browning on the tips and serrations of the leaves. Classic symptoms.

soil is hot and or your fed to much spray your plant daily lights off with only water and only water them for a while
also pray they come back

soil looks totally dry. the first time you transplant a baby, is the most important water in you will ever do. water em in good. so they are draining freely. and not too close to the lights, when young. if they dont have super roots yet, it will be to hard for them young uns to keep them sleves watered! let them start catching on, and give more light as you go.....

the soil is good , i just watered them yesterday and ive been easy on the nutes but ill try less next time. its been a month since transplant tho, and it wasn't that touchy of a process because i dropped seeds in rock wool and when they sprouted i put them in their grow medium (coco husk). they were doing fine until my second to last watering, my associate added WAY to much pH down. I didnt personally test the water but i can say first hand that the run off was a pH of 3.9...in case your wondering, yes i smacked him...but i flushed, started a light strength nute solution again, and now this, so for now i think im sticking with water for the next couple waterings. thanks for the advice people

Classic Calcium deficiency. Coco loves it...sucks it all up...leaves little/nothing for your plants...especially if you're using RO water...Botanicare's Cal Mag + and you should be straight.

http://www.barnesandnoble.com/w/marijuana-garden-saver-j-c-stitch/1100309181?ean=9780932551917

+1^^ good advice