Any idea what can cause these white/light yellow leaf tips, mostly on the newest leafs??
Might be light burn, it’s quit a powerful led (niello m-900) or maybe high on nutrients?
It actually is a little bit of both. The tips are slightly burned as you stated, but you can also see some leaf cupping which is a sign of light/heat stress. I would just back off of both a bit, take the light to about 24"-30" inches above the canopy and go a little lighter with the dosage of nutrients.