Zkittlez Autoflower

Growth has been steady since germination. They've both grown to be about 5 cm and are currently working on their 2nd set of true leaves. I've dubbed the plants Zkittlez 1 and Zkittlez 2 for identification purposes (in photos that show both 1 will always be on the left). Zkittlez 2 has been slightly more vigorous, though it shows some very slight browning on the tips of its 1st serrated leaves. I was worried this may be nutrient burn. Maybe my EC was too high, though Zkittles 1 doesn't show any brown tips and 2's symptoms haven't worsened in the past 3 days. I actually fed them slightly more Cocos A & B this time, though I brought the mS/cm down, so hopefully that helps prevent any issues.