I used the canna coco pulse.. pre buffered apparently to go with the a&b so you you can use it starting from the bag to the pot... apparently. I will try a small amount of cal mag in the feeds and see if that’s helps... only issue in my thinking is it’s only one two out of 4 plants that always get the same. My thinking now is maybe it was to do with salt build up as I started them in the 5 gal pots because I heard your not meant to transplant autos. I’m still not sure I watered them right at the beginning being in a big pot and a small seedling I didn’t water to runoff because I didn’t want to drown them or flush out any of the buffer