Lichtbrand light burn

I don't think the paling in pic 2 is light-related, because the foliage that is taller and closer does not have any damage. light damage will happen top-down for obvious reasons. So, that's more likely nute-related, i'd wager. Signs of too much light leaf damage - paling at first and worsening issues Extra droopy for many hours at end of light cycle -- to be clear, not just a little droopy immediately before lights out or cycling in and out of droop near end. extreme wilting - this would more likely happen if you took an indoor plant out into direct, intense sun light. stunted growth - easily seen by developing stem (internode) between growth nodes. with flowers you'd also see singed, yellow nubs where the pistils (hairs) would be located. *Sometimes too much light can take weeks to cause a visible issue. The plant may be able to tolerate some excess but eventually it causes a problem in aggregate over time. So, don't just consider the most recent behaviour. 680w from 40cm is quite close. But, proof is in the pudding. How the plant is growing and reacting is what matters and what you base your adjustments upon. suggestions and recommendations are merely a good starting point.