from growing a bunch of mothers in coco/hydro/soil.. when i do hydro moms, i always give a larger PK dose than the N...
I used aqua flakes A+B .. A at 3ml per gallon and B at 6 ml per gallon. Works great, make sure to add a little bit of calmag. letting the pH fluctuate from 5.5 ~ 6.0 always...