Throughly flush the soil.
That resets us to square 1. After a flush we no longer have a nutrient overdose/imbalance problem.
THEN, after a day or so, start using a full-spectrum quality nutrient. Start with 2/3 recommended strength.
If you're in pre-ferted soil, do the same as above but re-start nute's @50% strength.
Note: certain lights distort colors, but if the leaves are a lime green as the pic indicates, your plants are starved for N (nitrogen). You want a dark lush green.
Not sure on how long you plan ro let them grow, but 43 days in "seems" a bit late to be adding "N" IMHO.
I agree w/ ganga, on the color issue, but the damage looks more like heat stress than fert burn.."to me" Over ferting usually curls tips down "claw like" in my experience.
Hick you were right, a friend of mine who been growing for years saw the plants and said that it's heat stress and not to give nutrients till harvest, I was running my 1000watt dual spectrum at about 1ft and few inches. Although my grow room doesn't pass 75f since I got ac in it now.