I'm growing a lowrider autoflowering strain. Its under a 400w hps about 18 inches away from the plant, I'm using flower grow serious 10ml, 7.5ml, 2.5ml to thegallon in a 4 gallon tank with we other plants. I was thinking it could be nutrient burn because of the tips, but does the leaves yellow like that or is it natural? First time grower. Thank you for your input.