Root rot in coco

I keep getting root rot in cana coco. I water daily by hand 6.0 ph h3ads formula. I think I may be overwatering. What I belived was coco cannot be overwatered but even looking at canna coco website they say to keep it a little dry rather than wet. Grow tent humidity was pretty high and plants weren't drinking as much but I keep getting rot on some plants maby 25-30%.