Burnt tips? Or Nutrients

Is your diaries information accurate? I'd aim to give them plants some sleep. 20/4 is the maximum I would do for its light cycle AKA its photoperiod and I would only do this for a shot span of time. Ideally 18/6 is better suited to my need and light strength for any autos seed-harvest or vegging photoperiods. time on/off does not matter as much as DLI does. You can give a DLI of 40 in 12/12 cycle or in 18/6 cycle depending on lights strength and dimming capabilities. Its what counts towards good proper growth, to much light may result in a higher then normal DLI and excess is not better. I have not seen the first pics leafs symptoms before, it makes me wonder if it was something in the environment as its only on two of the finger on one leaf and nowhere else on the plant. The 2nd pic looks to be like it may be wanting some potassium. I would check your feeding ratios and confirm if it is lacking or not. I don't see what your feeding in your diary, best to update that. Last point is PH. 6,7 is ok but I would aim for that to be aorund 6,4-6,5 in soil. just a small decrease, nothing crazy probably won't matter but that's my preference. Good Luck!

It's interesting that you experienced an excess of nutrients in your plants without adding any additional supplements. This could have been caused by a new substrate you purchased. That's why it's recommended to choose reputable brands to ensure you get quality products and avoid unexpected surprises. It's important to consider that some plants are more sensitive than others to overfertilization. Each plant has its own nutrient needs and tolerance. Therefore, it's essential to carefully monitor nutrient levels and adjust them accordingly to avoid overfeeding. If you encounter an excess of nutrients, you can perform a root flush. This involves rinsing the plant roots with water to remove the excess nutrients from the substrate. If you observe healthy growth in new leaves and shoots after this, it's a sign that the plants are recovering well. Greetings, and I hope I have been helpful.