compared with the pots, one's being kept at 5.8Ph daily and the others just watered once a week.
If you are treating your coco plants like they're in soil, that is probably what's wrong with them.

Coco grows are hydro. You need hydro pH ranges and hydro nutes. pH 5.2-5.8 has worked well for me and colleagues.

Coco is intended to be watered differently than soil. Soil needs to dry out a bit between waterings--coco doesn't. In fact, if you let it dry out just a bit too much, your plants won't recover. Coco can be watered every day.

HTH, Hermie