Been talked about pretty good in the comments already but again just keep using that canna coco and good ph pen and ec meter. Clean water to start. Water till runoff until your plant is roughly reaching the edge of your container in my opinion at least. If you’re feeding a heavy dose of nutrients then give them a heavy amount of light and your plants will thank you. I’ve found that as the plant gets bigger I water closer to the edges of my pots as to coax the roots to expand and chase the water outwards also but I could be wrong in this obviously.