Cal-mag quiry?

That all depends, if you're using synthetic nutes some brands will have a certain percentage of calcium and magnesium where organic nutes don't usually. If your regiment doesn't have any included you can add it in once a week, the plant takes a few days from research to metabolize it. Some people swear its like advil for any type of deficiency but you don't need to over do it every feeding.

i just did what the bottle said which was 1.5ml/l and that got me out of my problems.

All depends on the many variables of your grow. That’s why adding a diary is vital for questions like this..

Hello buddy if it is cal mag from biobizz they say you can use it each watering in prevention with schedule of 0,5ml/L for week 6 to 8 and after week 8 put 0,8ml/L . if you have cal mag deficience you need to put more. 0,5-0,8ml/L for week 6 to 8 and after week 8 0,8-1,2ml/L . i hope it will helps you. Good grow. Peace