questins on nutes

okay so it has been established by several different people that i have a nitrogen deffiecency an i ordered some blood meal from greenway biotech how much do i use to be on the safe side and what should i use with it?

as i dont want N toxicity an i dont wanna lockout other nutes by giving too much nitrogen if thats possible feedback from anybody is appreciated im a noob

Botanic are calmag has a little n in it