Female Seeds Lemon Kush

So one of the plants decided to act up on me. I actually didn't notice last week as it was in the early stages. One evening i had a look at my camera monitor and 1 plant's leaves were a touch droopy compared to the others. I went and had a look and discovered the leaf necrosis. Damage is present from mid plant to the top. The lower half of the plant is normal and shows not even the slightest damage. I had this issue last year in a RDWC setup. It began close to the end of the crop so i never got to diagnose and reverse it before harvest. To me, the necrosis between the veins of the leaves and it being on the upper half of the plant, the closest thing i could think of is 1 of 2 things, either pH fluctuation damage, or a lockout. I flushed the plant with 5 Liters of water pH'd to 6.4. I collected some runoff and tested it's pH and it was 6.5 so I can assume it's not pH. So I flushed the plant 2 days ago with just pH 6.4 water. Today i checked on the plant and the damage, which was moving fast in it's spread, has seemed to stop progressing! Yesterday every plant with the exception of plant #6 (the sick one) got 1 liter of cal-mag water top applied. Plant #6 is still heavy with water from the flushing. The rest can go another day before they get watered. Tomorrow i will feed them all. Some of the plants are having trouble establishing a capillary action and drawing up the water from the bases. AC Infinity says the system will not work if there are no roots sticking out the bottoms of the fabric pots. Some of the plants it's working and some not. I don't know if my pots have roots growing out the bottom, I haven't looked. It would be nice if they all worked though. It's a matter of dialing it in that's all. Anyways, with the exception of Plant #6, I'm pleased with the Coco Coir medium. I love the manoeuvrability of the individual pots. I've always done RDWC so your stuck where you are. 1 Plant gets sick, they all get sick. Coco and Fabric pots are all right! We press on!👌