Overwatering/heat/nutrient problem

Multiple fertigations per day needs a properly sized plant to pot with appropriate drainage and aeration qualities. If it cannot drink at least 25-33% of the water befoer the next fertigation, you shouldn't be doing that. Fertigate until 10% runoff.. remove waste water. If not doing that, it will cause a buidlup of minerals in your substrate. Also, 1.7EC may be too strong. While it may look fine for 4-5 weeks or even longer, if signs of toxicity creep in that means it's too much. When you are close to "optimal" it takes a month or more to see the ramifications of a small error on the high side, I don't see anything in these pics that i'd react to... Slowly progressing issues are easy to diagnose but you have to be patient to allow the symptoms to clearly present themselves, then cross reference how you've feed leading up to that point --- not just recently but since the beginning. ratios and concentration... a good formula should not cause any deficiency or tox symtoms in 95-99% of plants. What you describe could easily be environmentally caused too. Best to be certain before you do anything. wind? temps? too dry? etc... could be trying to do multiple fertigations when the substrate retains too much water (water:air mixture should be close to 1:1). could be that the plant isn't drinking enough, even if it is a good mix (which 70/30 coco should be fine on its own)... how much weight is lost in that pot between fertigations? if not 25-33% i'd wager it is the frequent fertigations that are the cause of any lack of perkiness.