Yellowing on edges

I Have 1 plant that's a different pheno to the rest that has yellowing on the edges of a majority of leaves.
I'm using aptus nutrients, the full line up all organic. Putting out an ec of 0.7 and I've been putting in alot of calmag to bring the ec up to 1.2-1.3. Not sure what the issue is

Good reference chart

Why are you doubling your EC with CalMag? Seems like a lot, and too much of anything is bad.

The yellowing is reminiscent of a K shortage, but I'd look into all that CalMag first....it may be your issue at the end of the day. Good luck.

Given it no calmag for the last week. This Is the progress. Am now going to bump up the K and add that separately to the plant. All other plants are fine, this is clearly a different pheno than the rest and thus requires a different set of nutrient levels. It was the quickest to turn, quickest to bud up early and put on significant flowers, but has halted since and the rest of the plants have caught up and will overtake her, she seems to be frozen no development in atleast 1 week. Just hit start of week 4 today

If you're going to add K....be easy with it and be sure you're managing your pH to a T. There are nutrient absorption charts for cannabis...just google them. Be sure your pH is in line with the style of grow you're running and look at the range of pH...K will have a pH where it's highly available...be sure you're in that zone. Good luck.