Help, little ones so healthy, now looking ill

Alrighty. got it

@omegayak…I start feeding my DWC seedlings as soon as they have enough roots to be caged. Water level is kept just below, but, not in the cage. Nute strength is kept low until the roots grow long and thick. A week or two…and I will add ph’d water from the top as well as spray misting the seedlings twice a day with ph’d water…club soda at times-it provides CO2.
After a few weeks, the plants are growing long roots and healthy vegging. Then, I slowly increase the strength as the leaves indicate.
Important to learn to read your leaves. DWC mistakes will fry a plant to burnt hay.

PH is critical. I was using walmart citric acid for ph down…but…it wasn’t stable. Now, I am using GH PH down…it’s a mix of phosphoric and citric acids. Using it for a week now. It seems to be more stable. The walmart citric acid had to be chased twice a day…whew.