You don't need cal/mag unless you are using ro water generally, even then you may not need it, should be enough in base Canna nutes, that being said look into Jacks nutrients, WAY cheaper (like a ton) and have had excellent results. Jacks Hydroponic base, Jacks Calcium Nitrate and epsom salt (magnesium sulfate). Very clean nutrient line. You can add fulvic acid every few weeks as well as a chelator. You can look into adding microbes (teas etc) as well for additional benefits/health but would require res changes more often in dwc imo.
I used Canna line (complete line including boost) for a few years and had great results with it.. switched to Jacks 321 a number of months ago (also tried mega crop with good results just not as clean for hydro (humid/kelp/molasses maybe in it too), I am kicking myself for wasting literally thousands of dollars on Canna when Jacks has been performing just as good if not better. Great video on jacks here.
Many organic nutes (if not all?) are only available to the plant via microbial breakdown/waste.. so unless you have an organic system organic nutes are a no no in hydroponics.
Ohh also, keep the water cool, use a chiller if need be, try to keep it under ~70f to help reduce chances of root rot and to keep oxygen levels up in the water. Higher the water temp the lower amount of oxygen it can hold.
