help please

I've got 2 cheese plants in canna coco and I'm using canna a+b nutes, the plants are fine except for one small problem, the tips of some of the leaves have turned white/yellow, does anyone have any ideas?

Much appreciated, I'm new to this forum and this is my first post, so hello to everyone!

I don't use canna coco but i'm almost positive that you have over fertilized JUST A BIT.....just some of the ends of some of the leafs are yellowish white.....

i have 6 blue cheese ladies in dwc buckets at the moment.........