PH distilled water?

For starters, your going to need some ph up/down to add to the water. also distilled water normally has a low ph like 4 or 5, so flushing with the distilled water until runoff comes out to what you're looking for, I would suggest bringing it down between 6.0-6.5. Hopefully, I answered your question and remember Happy Growing and Free your mind one puff at a time.

I am going to tell you what you dont want to see, Jorge Cervantes wrote a great book on growing canna in soil. On amazon... read it

Your plants are fine dude.. looks really nice.. Ph is important when it comes to seeing deficiencies or problems... like 75% of the time growers either use too much (dark green is not a good colour) or there ph is super out of whack from there own hands... I see a bit of what could be interpreted as yellowing.. or normal healthy growth... yours plants should have a variation or difference between newer and older leaves.. Newer leaves should be lighter in color while older leaves should be darker... Phenotype expression happens much later into flower so in veg your plants should look relatively uniform even when growing different strains..

@Mrs_Larimar is correct... Quality Soils.. Containing peat have buffers to keep your lady healthy... I will take a good look at your plant and let you know if I think it's ph... I see ph issues a lot as I grow hydro Even something as simple as the spring run off raising my tap water by 100 ppm.. Throws the balance off..

Can just buy "PH down" if you want to lower the PH in your soil.