Go to canna uk website and work through the nutrient calculator.
Base it on light feeding schedule.
This will give you an amount to use based on how much you are mixing.
In order to do it effectively an EC tester is a must.
BlueLab EC truncheons are shit hot! Around £60. IMO pH isn't as crucial but if you can afford it get yourself a pH tester too along with the calibration solution. £40.
I used to run EC and pH at the following.
SEEDLING 0.8EC pH6
VEG 1.2EC no higher pH5.8
FLOWER weeks 1-3 at 1.4EC p5.6
FLOWER WEEK4 pk1314 at 1.5ml per litre then add nutes upto 1.6EC pH5.8
REST OF FLOWER EC1.4. pH6
Dropping to EC0.8 for around 2weeks at the end pH5.8
J