First time coco grower

They are not growing because you have them in totally inadequately sized tiny cups. At this size, they will already be root bound in those tiny cups. Black plastic pots about 4 inches across and 5 inches deep are almost ideal for the first 3 weeks of a seedlings life. If looked after and cleaned between grows, the black plastic pots will last for years and also provide the totally dark conditions vital for root development. Also, your seedlings do not need to be covered or have artificially heightened humidity, they need good air exchange for proper growth and good air circulation for strong stems. Hope this helps,.......... Organoman.

Dropping pH in runoff is often due to overfeeding. Test your EC in the runoff, I'd be willing to bet that it's a lot higher coming out.

Dont worry over PH runoff in coco DTW I assume. You can check PPM it has some meaning but PH is not useful on outgoing.

Vegetation COCO - 5.8-6.0 U are above average

Water at 5.8.

Veg in coco is 5.5 to 6.0 ph. Flower time ph is 6.0 to 6.5. Your ok. Cheers