Top leafs tips change colour

Thank you very much to all of you for taking your time to answer to me. The new nutrients might be from the fresh soil in which they have been transplanted from in the bigger pot 2 days after the flush. The burning did not spread and it remained fairly the same. Watered with clean water yesterday and they grew a lot overnight.

Looks like it could be early nute burn. The tips will stay burned but shouldn't affect the grow. I see in lower comment you already flushed. So it probably just burnt from the overfeeding from before. Probably don't need to flush again unless it get worse.

Yes. It's the beginning of nitrogen burn most likely. Dial back a touch on nutes with nitrogen. New leaves will be cool.

oh, and could still be pH related too.. that can cause any and all tox or def symptoms if out of whack. it's happening at top = mobile nutrient -- helps deduce what the actual issue is when armed with enough information otherwise. if you think all other factors are normal, lower pH a tad. The reason behind hydro vs soil having a lower pH is actually to slow down plant chemistry in hydro. So, a lower pH will slow down some of the nutreint use (not all) and if that is the cause it'll help even out the ratios of use within plant to a healthier level. (even if in soil, meant as a conceptual understanding how to use pH as you react to the same observances regardless of the substrate and cna wield it in similar manipulative ways as chaning formulas or concentrations of what you feed)

read comments -- not symptom of light burn, can rule that out. Lux doesn't travel well, so if you read somethign based on a lux measurement, discount it completely unless you have the exact same spectrum of light and all other relevant factors, otherwise it is oranges and apples.

dial back on nutes, looks like burn. if you don't have the info, calculate out what you feed your plants from labels... start keeping track or you can never have a solid answer to these questions.. always a guess.. always a chance the "fix" makes it worse.

The runoff water is at 6.5 as my medium buffers the pH down from 7. If you see my diary, you will see that they came from seedlings directly into a 3l pot, so I am familiar with the watering of a plant in a to big pot. It is interesting that it is the new growth that seems to lack something, or perhaps the approx. 45k Lux were a bit top much. I have moved the lights up a little. I will keep an eye on the situation.

These are my thoughts but I am not a professional so far but sometimes taking problems with another look can be interesting 😉

Your at 7 ph is too high, the plant does not access the resources as it should, try a ph between 6 and 6.5. Also pay attention to the size of the pot when watering if the roots have not yet taken up the whole space.

I flushed it more than a week ago because was presenting signs of nitrogen over feeding. Since then I did not use any fert. I have only transplanted the plant from 3l pot into 14l pot. I have used BioBizz Light mix since the beginning.

I'm thinking of too much fertilizer