I think it is really difficult to over do it with canna coco + AB. I've been using it for a while now and in the worst scenario you get to much leaf. Canna recommends pre-buffering with calmag to saturate the coco with it, I think I remember from a Canna training I saw once online that you need to pre buffer it with calmag and that later it will be taken by the plant, if not done like that, the coco will take cal from the plant until it gets saturated.
"Coco substrate that has been pre-treated in this way is unlikely to release excess potassium or bind the calcium and magnesium that the plants need. The result: healthy plants with no symptoms of nutrient deficiency."
"Some coirs have been chemically treated, this is most often the case with loose pre-hydrated varieties versus compressed blocks. The treatment has been done to satisfy the cation exchange capacity (CEC) of the growing media. As a refresher, “cations” are positively charged ions, such as Calcium, Magnesium, Sodium, and Potassium. This means that the growing media will hold these ions in a matrix, releasing them as required by plants. There is one slight drawback to this. Until the cation exchange capacity of the growing media is filled, the growing media may hold positively charged nutrient ions, most notably calcium, in reserve, making them less available to plants. However, the cation exchange capacity (CEC) of the coir media is quickly filled, and actually assists calcium absorption in the crop cycle. To ensure optimum availability of all nutrients, supply additional calcium during the first week of growth or during the hydrating process of the coconut coir. Calcium supplement products are ideal for this. Some nutrients specifically formulated for coco tend to have elevated levels of calcium and magnesium while having lower levels of nitrogen. "
so, if you are using out of the bag canna coco, you should only add rhizo, calmag is not necessary for canna coco unless you see a deficiency and sometimes I use it to raise PH, adjust ppms or to refill the coco with calmag due to the regular exchange. LEDs are said to require more calmag and indeed since started using it I stopped having problems, but at the same time I noticed a chalk like flavour on my buds so right now I use it only if I notice a problem or now and then just because.. plus, AB is supposed to have all you need.
If you ask me, I think you green could be darker, I would just add 4ml in 4L ( my measure ) of AB + Rhizo.
