Both man, you want to adjust the pH of the coco up to 6.5-6.8 with dolomite lime.
Then, before you water or feed your plants, always adjust your nutrients to 6.7-6.8 and you will never ever have a pH problem. Coco is that simple.No way to screw it up as long as you always know what you are feeding em and what the pH is.
I would suggest anything organic for coco, and don't believe the hype cause you dont' need anything specially fomulated for coco.. it's horsecrap.
ANy good nutrient line, whether fox farms, Metanaturals(my choice), Botanicare( most any brand of theirs) and many others.. even the alaska brands work well with it.
Coco is forgiving.. you made the correct choice to start with it.
Just remember, you are going to have to feed every water, from the time the cotyledons fall off, till the time you harvest. Especially if you run straight coco. Coco has nothing that the plant can use. It is naturally barren.it looks like soil, but def is not
.
Another tip is to start your seeds in a good organic soil, and transplant to the coco. Coco doesn't tend to germinate seeds well unless you cover the containers with seran wrap or a humidity dome of sorts..
Follow these tips and you won't ever have a problem.
Anyways, search the web for coco info.. its' there but few and far in between ...mjp has a whole forum devoted to coco.