yum!
Do you have an organic PH down for your coco?
I have a feeling that the Nitric Acid in PH down (or Phosphoric) will not do the organics any favours .. I have something in my mind saying it should be done with citric acid (lemon juice).
My Biobizz soil will buffer to some degree, and the water i'm using has been tested on a couple of biotabs grows.
Just an after thought as you're doing coco! ^_^