Canna should work, other i dont know. You could als use blackcurrant water mixture or thinned coffein free coffee to feed her. Good PK sources are everywhere in nature. NPK 20-11-12 (200-110-116 mg/L) showed the best results of all, thinkness of stems, numbers of leaves, etc, study is i think week 9 of my grow. What i see with your grow, you water too much or you water from top, you see it on the eagleclaws, thats why they develope slower or are yellow, other is you have probably too less light power for the downer layer with these huge plants, thats why they dont produce so much thc. You could add some led panels, what adds light with a ~60 degree angle/vertical position to the downer 50%. The resin is a UV blocker to protect the plant from sunlight. With a UVB bulb (reptiles) and some co2 yu plants will be stronger. BUT: In this stage i wouldnt give much nutrients anymore, only one time maximum, she should use the energy of her leaves, so the taste will be smoother. Add some light from the sides and water from bottom (dish) and probably half the amount, my recommendation Fertilizing to late means "you smoke the not used nutrients".