First grow, first post, need help (pic heavy)

Hello folks. As the title says, this is my first grow and my first post. I have quite a bit of experience gardening, just not cannabis. My girl is in the early flower stage, and I have recently noticed that her lower fan leaves began to yellow and die. There are also small brown spots on some of the middleish leaves. I have also noticed that yellowing is begining to move up the plant, but only seems to effect fan leaves on branches with no bud sites. The yellowing is only in the tissue between viens and the worst of the leaves are begining to brown and die around the edges. I fed her on April 19th and began noticing the yellowing on the 22nd. Some of her stems are also turning redish purple. I have a few ideas of what it may be, Nitrogen or Sulfur lock-out, but I would greatly appriciate as much feedback and advice as possible. I'm just confused because I wouldn't expect to have a Nitrogen issue this far into flowering. I also just want to ask if anyone has any suggestions to combat the problem and if this will effect her harvest. Thanks in advance for your help! So here are the details:

Strain: Delicious Seeds Critical Jack Herer Auto
Set-up: Stealth 2 drawer nightstand; about 24"x18"x20"
Lighting: 6 23w CFLs; 5 x 6,500K and 1 x 2,700K for vegging and visa versa for flowering; 18/6 for entire grow
Water: Distilled
Medium: Started in 16 oz. party cup with 2 parts F.F. Ocean Forest and 1 part 50/50 mix of peat and perelite, finished in 3 gal. grow bag with only F.F. Ocean Forest
Nutes: General Organics Grow Box, I used the light feeding guidelines when applicable and 1/2 of the suggested strenght when not
Temperature: 82-88 during the light cycle and 62-66 during the dark cycle

I watered her every other day while in the party cup and every third day while in the grow bag. From the time she developed her third set of true leaves untill she showed sex, I fed her Black Diamond, CaMg+, Bio weed and Bio root with every other watering. At first sign of flowering (April 16th) I fed her Bio-thrive Grow, Bio marine, Bio weed, Bio root and CaMg+. For her first feeding during the flowering phase, I fed her Bio-thrive Bloom, Bio bud, Bio root, Bio marine and CaMg+. I wasn't too worried about PH, but I bought a Burpee soil PH meter and it was sitting at around 6.7 or 6.8. Now on to the pics...

How dry is the soil? Try digging down an inch or two with your finger to see if there is moisture, my plants looked exactly like that when they were under watered.

The reason I ask is because pick 5 and 7, the soil looks very dry.

They look overwatered and heat stressed, possibly deficient in mag.

She is pretty dry right now because today was watering day I've just been holding off in case I decide to flush her. By day three the soil is usually dry about an inch down though.

if this is your first im pretty sure its because your overwatering give it another day also do you have to use distilled? I consider distelled water too clean try to use the tap just make sure you set it out for a day to get the chlorine out.

Thanks for the quick responses.