Need help before it gets worse

set up:
DWC
R/O water
GH nutes flora series,cal mag,rapid root
PH: 5.8
PPM :400
8x 23watt CFL (day light)
TEMP:81Fday/75Fnight
RH:41%day/50%night
4x3x7 box in closet
inline(room air) and exhaust(to outside)
plant is 3 weeks from seed

I have done a ton of research all I see is that its Cal deficiency but im using cal-mag 1tsp per gallon using 3-1/2 gallons of water = 3 tsp is this not enough? or is my PPM to low? This started after the second week when i started to feed I did start with 580 ppm after i noticed the spots i brought it down to 400 ppm and it looks like its slowly spreading. Its only on the the first 4 tru leaves, can someone advise on what to do while shes young??

what soil? I think that's a mag deficiency I use FFOF and another guy who uses it says you need cal+mag. I just let mine go they got so bad im going to bury some soil over them tonight if you dont want them to die that's the way. There's a product that works perfect i forget what it's called i've never used it i'm sure someone will throw it down on here.

Hey, Greenrush, I've had so many young plants do this that I don't even worry about it anymore. I've had this problem in brand new soil, in hydro, you name it... The best I can usually chalk it up to is that the young roots and the young plant are just working out how to best take up nutrients. When there are more roots, bigger leaves, more stem, etc., and the plant is booming and actively consuming the nutrients you are giving it, I find this problem goes away.

That being said, my initial response to that kind of coloration would be a cal/mag adjustment. But since you have already said that you are doing that, the next best step in growing marijuana is always and I mean always do less to your plants than more. What I mean by that is, don't misdiagnose a nutrient order, attempt to correct it by throwing more nutrients at it, and only cause the problem to worsen or branch into further deficiencies of other macro or micro nutrients. Whenever a plant starts to show a little bit of a color change, always give it a couple days before you do anything. Watch what she does. Most times, she'll bounce back.

As you grow more you'll find that you almost never need to baby your plants as much as you feel like you have to in the beginning. We all start off with so much money, time, love, and research invested in this that we tend to over-worry and over-baby our plants. Once you've grown a few dozen out, you start to see that you can snap them in half, all the way over, break their stems, not water them for days, and they will adapt. They will overcome.

You should of course never intentionally abuse or neglect your plant, but as you make mistakes as a new grower, take comfort in knowing that the plant is strong, and she wants to live. She'll find a way. Happy growing!

Thanks for the advice this helped a lot. I do feel like I need to baby the plants in the young stage so I'll take your word for it and not worry as much. Thanks again I really appreciate it.

i dont use soil its DWC the medium is rockwool and hydroton