rhodes68answered grow question 5 years ago First thing is you have to decide are you doing a hydro grow (the best) or a soil grow with coco (not the best).
Dr MJ Coco has a book on amazon read it today, if you want to grow a lot of canna.
Right off small plant in a big pot slows growth badly.
Secondly and this is why you have to decide, throw runoff PH right out the window for hydro. Its just not a factor.
Your PPM for runoff is saying it needs to be fertigated more often, if its hydro, if its not hydro throw that right out the window.
You have to choose a course.