hammerhead p k - what amount per litre?

just wondering how much to add per litre - im heavy feeding right now, but the neut calculator at an doesnt have a feeding for hammerhead - im doing it at 1 mil per litre at the moment...

hornsby hammerhead is a hydroponic PK boost, but you can use it at half strenght in soil, that is unless you have an outdoor hydro set-up then you would follow the exact directions on the bottle,,, soo long story short! hydro nutes can be used in soil but only at 1/2 strenght