If you check my OP you'll see the nutrient schedule I use. I use the same for every grow and just added CalMag for this one as the girls were showing deficiency.
I got it from another Canna Coco user who just took the schedule given by the manufacturer of the nutrients and dialled it down for better results after a lot of trial and error.
All nutrient manufacturers will tell you how much to use and when but growers find most advise to use a lot more than required which is why a lot advise to flush every couple of weeks.
It depends on the nutrients you use, your mediums and your grow style as to how much to use and when.
A lot of nutrient companies have calculators on their websites