That stuff is coco and peat. You need to maintain a pH range of 5.7-6.2.
Due to the fact that it's coco and peat mixed, I'd highly advise that you periodically swing the pH. Start at 6.0. After a couple of waterings, 5.7. Couple more, 6.2. Couple more, back to 6.0.
Do not pH all the way up to 6.5.
This will ensure maximum nutrient uptake availability.