Hey erocknroll ,You will need to add cal-mag.I use calmag+. I use @6mls/gal for the initial waterings (2-3), then reduce to 3mls/gal until the last week, if over used you can get some lock-out of other element's (strain dependant,light,temp etc.).
I have been using H&G cocos a&b for 15 years now...