What's up with my girl? pH? deficiency? Scabies?

Having some issues with one of my girls. They're in buckets layered with potting soil, peat/compost, and rocks at the bottom of the bucket for drainage.
Now I didn't set these up (I recommend against partnering up btw) and I wasn't impressed with the way they were set up, especially since theres ZERO perlite, rocks or anything for drainage. As you can see, she doesn't seem to be liking it. There are four plants in this setup, none of them responded well, but the one White Widow took it the worst...Here are some pics of the rest, sorry about the stripes, I didn't remember to turn off the HID



I started to pH the water and feed them some GO Biothrive Grow and some CaMg+. After a week two of them perked right up, and another 1/2-1 week for the third plant to respond. It's been almost another week since the last perked up and at best the WW stopped getting worse, but it hasn't seemed to improve.

I checked the pH and noticed that the peat/compost is around pH 6.0 but the top layer of potting soil is at a pH of like 7+

Any suggestions on how to get my girl back to normal and happy again without pulling it out of the bucket? I'm worried that it has been set back so much it may not recover

Start with a good flush on all plants. Run 3 times the size of the pots to water through them. Ie 1 gal pot runs 3 gal of water through them. This will wash out any salts or build up of other nutes that may be built up in there. Give them a day to dry back out and mix up a light feeding maybe no more than 480 ppm make sure your in the optimal ph range for your medium. And you should start to see the plant perk back up. Enjoy

How well do your buckets drain? They look a little wet and over fed to me..