Damaged leaf

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TDS Pen results: 0,5Liter filter water: PH = 4,9 TDS PPM = 11 EC μS/cm = 22 add Nut mix (advanced nutrients ph Micro Grow Bloom) M 0,5ml G 1,0ml B 0,5ml PH = 4,89 TDS PPM = 300 EC μS/cm = 6l2 So the PPM is 300 to high? what EC do i need? Or do i confusing something TY

you will want to invest in a TDS pen, this will tell you the PPM and EC of the nutrients you put in water. Your plant can not handle over so many PPM or a high EC at this stage in its life. AN can be used at 1/2 or even 1/4 strength when it is a seedlings. I'd aim to keep it aorund 100-200 as a seedling and working your way up +100 every week till you hit 600. Only adding in more if the plant look hungry and removing some if it is over fed. This changes when it enter flowing stage. also autos need even less then this and are extra sensitive to nutrient burn. One last note is that if your watering with no run off. less is more. if your watering to the point of runoff you should also test the runoffs PH and EC to ensure its in the propper ranges your looking for. Good Luck!

Thank you very much for your advise. Nice this would be my next question, so i leave them on and dont cut them off. Yesterday I repot it again with dry soil and added about 200ml Water + Advance PH 3 component mix. Its fairly dry now, because I was a bit scared of a NutBurn. I will keep the light now at this rate and position. How many water+Nut mix i can feed per day and how many times? The instruction from the component mix says : mix 1ml/Liter for one week. so i give 142ml water per day or all at once, or every 2-3 day halt liter? I kinda struggle with, how much water+nut mix is enought but not too much. Thank you

That looks to be a bit of light burn and or overfeed. All the new growth is looking good, so you appeared to have corrected the issue. That leaf will not fully recover but will continue to live with some crispy bits. Don't cut it off as the plant is still young and is using it. You can remove it later once the plants bigger. Also try not to get the leaves wet when you water. The light will burn them as the droplets act like mini magnifying glasses on the leaves. Good Luck and Happy Growing!