Coco coir? Rinse well with pH'd water. They tend to be salty, even if they wash and rinse.
I'm not the best with coco coir, I'm all soil. But maybe 10 years ago messed with some and rinsing through is almost always necessary. I would email the manufacturer, if they don't respond return the product and find someone that will.
Someone else chime in here?
Rinse. Dry. Rinse. Dry. Repeat.
Note on rinsing, make sure your not rinsing with water that has gone through a water softener, basically you would be adding salts to it. Also knowing if you have RO or distilled water that is pH'd will be absolutely necessary. Otherwise, again, you could just make it saltier.
Best of luck. There are a ton of great growers on here who use coco coir. I am sure someone more experienced would say similar, if not the same thing. But let's see what they say for real.
❤️ you got this. Also think about soil, lol, I don't want you to change your whole set up, but if you are in the design stage, before already made purchases, think about soil. Both are great.
❤️ 💙 💜 💖