250 ppm burned tips ph 5.7/6.4

Hard to say which micro u are using? There's a few. For instance jungle juice micro is very strong and any sort of micro this early is too much. The micro is for the flowering phase. Focus on the growth. If you are reaching that PPM with just micro, it's too much pal. 1ml/l is more than enough of micro. But you need to introduce grow, as most micros don't have N in them. Good luck.

The check ph every day is for hydro. check your runoff ph after every watering and keep it at 5.8 throughout veg. Not suppose to go past 6 in veg. That part of your problem.

This is a hydroponic or a soiless grow, coco or peatmoss feed chart. Make sure you ph your water at 5.8 for veg, check everyday. Feed chart for photos. Day their born, 400 ppm, 0.8 ec. See good growth that week up to 500 ppm, 1.0 ec. Next week and you see good growth, 600ppm 1.2ec Every week you increase 100 ppm if your seeing good growth. If your not seeing good growth then stay with that amount an extra week. Stop increasing when hit 800 ppm, 1.6 ec. Only give more if you see they really need. Soilless recovers or goes bad very quickly.. If their autos start at 200 ppm from sprout and work your way to 600 to 650 ppm.

After i decreased from 600 ppm, looks like it has gotten better, but it it is still getting burned. The top roots are in about 1L coco medium. Might it have something to do with the coco?