New leaves have white tips, other leaves have mixed color where its's mostly darker on the edges. Plant seems weak. Please advice on issue.

2x auto, 11L, 50/50 coco + soil (canna), Migrolight Aray2 on 60%, 50cm distance. Switched from 40/60% end of week 3, but also hang the lamp higher. Week 4 veg, only PH6 water, 1 liter every 2 / 3 days, 1x calmag week 4. Trying to do everything right. Need some good advice. TYVM!