
ryan, if this is the coco-specific Canna nutes, you don't need additional Ca-Mg, it's boosted already in them,....too much can cause other uptake and pH issues,....
...are these stand alone pots? If so, are you doing 15-20% run-off each time you feed? This is necessary to keep nutrient build-up from getting out of hand; you can't treat coco like soil it's behavior is very different from true soil, more like hydro; also you should be monitoring the pH and ppm/EC going in, and coming out, that's how you tell if the nute salt build-up is in check,.... coco has some odd CEC properties, so water alone is not recommended or it may screw up that cation exchange capacity which involves mainly Ca, but also Mg to a lesser extent,... it will bind to the coco and be kept from the plant until the coco is saturated and starts releasing it like it should,...
Symptoms look mild, early,.. probably Ca, but P defc. can do similar things at times,... all your feeds are per gal, not L? Is it what the bottle directions recommend? Seems weak per gal,...per L is m ore like it,... Do what you can for measuring pH, but if you grow coco, it's pretty much mandatory to use a quality meter and a TDS/EC meter too,... again, think hydro, without these, you're running blind and that will end up a shitshow every time, save sheer dumb luck,...
For the $, the Accurate 8 soil pH probe is the best for in-pot measurements, but if you're doing the proper run-off testing thing, it not really necessary,.... the cheap meters are crap, just like my mate
Yeats' here says,... :smoking:
Flushing in coco is very different from soil/peat based soilless... If absolutely needed, you use RO/Di water, with 150ppm Ca-Mg plus another 150ppm nutes, pH to 6.0, and poured through until r-o is at or near input values,.... you are not there with this at all,...