Coco coir urgent help needed :(

My girls are 4 weeks old, in 100% Plagron premium coco (supposed to be buffered and prepared), 250-300ppm feed, tap is 70 ppm, PH 5.8-5.9, using full Plagron line nutrients for coco +APTUS REGULATOR and APTUS Startbooster (mixing order - regulator => base a,b => everything else), stunt in growth, after seeing new growth light green, 10 days ago, thought it could possible be a lockout or something, based on the local hydro store guy recomendation bought flashing agent and fully rinsed with GHE/T.A. Flash clean (after 12 hours of keeping Flash Clean in medium) rinsed with fresh nutes 250 ppm (-tap 70ppm) (runoff was 320ppm).

I am feeding my other same age girls with the same nutrition mix and they are growing like crazy (6th node already) but they are in soil

Could it be the foam glass I layered on the bottom of each pot (0,5 inch) for drainage? I did not prepare it as well, cos it was supposed to be already rinsed and ready to go, at least what the hydro store guy said so...

Happy new year guys, please help me save my girls if it is still possible!
Tomorrow will be installing the RO maybe it will help...

Tbh, never trust a shop or brands claims of "pre buffered and washed". Not sure that's the issue, but something to keep in mind.

I ran pinegro "pre buffered and double washed hydroponic grade" Coco and on day three I tested the runoff. 6500ppm and pH 5.1. Have also used a coir block which was apparently pre buffered and washed. It came out at 5900ppm and the plant stunted.

I've always had far quicker growth with Coco than soil, and I ran 3 gal pots to runoff daily from day one. None of this half hearted watering. Even saturated, Coco has near on 25% air capacity.

What kind of light are you using?

Maybe try cutting out all the bullshit additives and just use the a+b mixing to 300-400ppm (0.8ec max). I had a similar problem using an entire nute range, 3-4 weeks in. I was blindly following the chart ratios but by half even! They were getting too much shit they didnt need and then couldnt take up anything at all.

I flushed the shit out of mine with 5.8 water, then started feeding using just a+b (I've since introduced back some silica and recently pk booster due to stage of flower.

VincenzioVonHook said:

Tbh, never trust a shop or brands claims of "pre buffered and washed". Not sure that's the issue, but something to keep in mind.

I ran pinegro "pre buffered and double washed hydroponic grade" Coco and on day three I tested the runoff. 6500ppm and pH 5.1. Have also used a coir block which was apparently pre buffered and washed. It came out at 5900ppm and the plant stunted.

I've always had far quicker growth with Coco than soil, and I ran 3 gal pots to runoff daily from day one. None of this half hearted watering. Even saturated, Coco has near on 25% air capacity.

Click to expand...

I always rinsed my coco too, I’d rinse it until my ppm were less than 250 ppm, then I’d let it soak with ca and mg enriched water for a while. Then rinse until my runoff was less than 250 ppm and then it was good to use.

Rinse the coco and presoak after with cal mag.