1st time grower - Please help with diagnosis

[Gushers]

I am a first time grower nd so far everything has been great. I flipped my babies to 1212 about 6 days ago. The pst 2 days this one plant went from hero to zero. I am not sure what is the problem as it seems to only be affecting this one plant. Any help and guidance is greatly appreciated!!

What Strain is it? Plant in question is sour d
Is it Indica, Sativa or Hybrid? What percentages? indica
How Many Plants? 12- 8 sour d and 4 jack here
Is it in Vegetative or Flowering Stage? flipped to flower 1 week ago.
Indoor or Outdoor? tent grow
Soil or Hydro? soil using roots organic 707
If Soil... What Size Pot? 3 gal fabric pots
Size (Wattage) of Light? How Many? 1x mars hydro 1200
Is it Air Cooled? yes
Temperature of Room/Cabinet? avg temp is 72-79 f
Any Pests? no
How Often are you Watering? watering every 4 days. let them dry for 3 and water n the fourth
Type and Strength of Fertilizers used? fox farms trio with pro silicate added
Size or Square Footage of Room? 16 sq ft


All were grown from clones

Thank you in advanced!

Pics:

The bad:

Here is a healthy sour d:

and here is a healthy jack herer:

Sorry for the blurriness of the last two. I didn't notice until i uploaded them

I have feed them all the same way with the same nutrients

Pleae help! i do not want my little girl to die!

 

[iwltfum]

If all the conditions were the same as other plants that are healthy, you're probably looking at either a virus or bugs. I would check the run off pH in case of a freak pH problem, but if I were a betting man, I would bet that the pH is as stable as all the rest of them.

 

[Gushers]

So update. i flushed them last night with phd ro water. Got some better cleaner pics. it looks like theres two plants affected actually when i water i mix 4 gal in a 5 gal bucket. i then mix nutes and ph then i use plastic cup i got from baja fresh to dip into the 5 gl bucket and i use to easily water the plants. i get bout 6-8 cups per bucket and water evenly amongst the plants i do about 3 buckets for a total of 12 gal so 1 gal per 3gal fabric pot. im thinking when i go for the last cup i pour the bucket into the cup and i notice someimtes there is extra sediment/nutrients that settled to the bottom of the bucket. i normally try to avoid using that part but i may have emptied the extra sediment/nutes in a cup making it more concentrated than others. could these be causing nute burn? does this look like nute burn to you guys? Should i just continue to flush the plant for the next couple of waterings? there was some new growth i think today and it looked better. any help/tips/guidance is very very appreciated!!

Here are some updated pics:

close up:

Here is a pic of what think is new growth on this same plant:

over view of same plant:

Here is the second plant that i noticed is having the same thing happen:

more of second plant:

Here is one of the healthy sour ds

another one:

and a big shot just so you see what im dealing with, the back four are jack herer and that is why they look taller

Thank you in advanced for the help!!!