Problem in coco coir

Hi

Most of them are looking like these.

R/O Water Ec 1.8 pH 5.8. Water temp 18/21 Celcius.

Ambient temp 24C. 65-70% humidity

Any opinion? I tried many different watering strategies, no improvement. They are drinking but can't make symptoms go away. I suspect FeEddha is expired (bought it in 2022). I prep the nutrients by myself, never a problem

Have you measured your runoff EC? How often are you feeding each day? What is the PPFD? Is that coco and what else in the media?

Looks like more than just coco.
I suspect salt build up and lack of oxygen.
Plus your EC is a bit too high.........I rarely go over 1.2.
Consider flushing the crap out of it with a low EC nute solution.

I think they need more food. I would put the pH=6.2 or so if it were my responsibility as well.

I agree with Mick. Flush them with a low ec solution until runoff is close to what's going in. How often are you feeding now and are you doing so u til you have substantial runoff?