Growing Blue Dream 1st time

SEEDLING WEEK 1 I am going to call this and next week the seedling weeks, or until a couple of sets of leaves have come through. So far everything is going nicely. The first set of serrated leaves are slowly getting bigger since it sprouted on the 17/10/21. It is now the 20/10/21. The plants have grown to between 2-3 inches and I have moved the light to 4 inches from them. I moved it closer to try and prevent stretching of the seedlings which appears to be working. I spray them either once or twice a day with regular tap water from a spray bottle. The 18/6 light cycle seems to be doing well and I don't have any light burn. It is now the 23/10/21. Yesterday (friday) I noticed some yellow and browning of the leaves on one of the plants. It appears to be heat stress. I have raised the lights 2 inches, making them 6 inches from the top of the plants now. Additionally, I have changed the light cycle from 186 to 16/8. I am doing this so that the plants have longer to use the energy absorbed throughout the day and put it to good use. The other plants, which is about 1/2 an inch shorter has no evidence of heat stress on it.