What is wrong

Just do it all slowly.
It'll take a few days.
It'll come down.
6.2 in your runoff is pretty good.


Coir is like a sponge.
Definitely rinse and wash it next time.

Just chill a little.
Plants will be fine

Another thing with coco is not all coco is the same. I typically use Botanicare cocogro 5 kg compressed bricks. It's double washed and nutrient buffered. I just re-hydrate with 1/4 strength nutrient solution and use it. I've had other coco in the past that had terrible results unless it was washed numerous times.