Yellowing and dry/brittle leaves

Hey, buddy! 👋 In coco and soil-less mixes, there can't be overwatering; coco has a high salt permeability, and they just wash out with new watering, while the roots always breathe and always have enough oxygen (and you can never have too little oxygen!!). If you're watering at this age, !no more than 10%! of the substrate volume, and even every day - just like it should be! Collect your drainage; if there's a lot, measure the drainage output (if you want to understand how much she's eating) and leave it; she'll drink it in an hour. Try to pour water into your coco very carefully, without washing it away, because there can be big roots 2-3 centimeters below the surface, and the plant will be subjected to unnecessary stress. Set up a drip irrigation system based on a plastic tank, with an outlet at the bottom for a 5-8mm drip irrigation tube. Placing the tank above the pot will allow for water to flow down the irrigation tape. It's not expensive to do it yourself and will pay off in the future! The plant will thank you! 👌 It's really hard to diagnose. Your diary doesn't have information on what your ppm solution is, what the pH of the solution is, or what the drainage output is after watering (water 10% of the substrate volume at the age your girl is!). It's clear you're feeding her well; she definitely wouldn't need an increase in nutrient dosage! 👆 Most likely, the problem is pH! At this age, she should have 5.8 pH in coco and its mixes (without soil). You have a good lamp, but it might be too close to the plant; check the lighting at the extreme growth points of the plant and on its sides! Bridgelux/Epileds LED with good potential... I would even say that Bridgelux is just what you need! Epileds - the kingbo manufacturer decided to save a bit. 😉 You can measure the illumination (lux) in the cultivation area above the plant! Install a free app from the market called "luxmeter" on your smartphone, clean your phone screen well, removing grease and dirt. The light sensor is located on the screen part, which often rivals individual lux meters. Check the illumination above the plant. Adjust the lamp height so that it doesn't heat the plant to shock states but stays within the lux range. Install the app; you'll remember me more than once, buddy! It'll be like a compass for your lighting! 👌 Effective illumination ranges, starting from planting the plant: Day 1 (250-500 lux) Day 2 (500-1000 lux) Day 3 (1000-2000 lux) After five pairs of leaves, full vegetation (2000-20000 lux) Flowering (20000-100000 lux). Try not to exceed 99000 lux. Otherwise - there could be problems! 👆 And I looked through all your weeks. In your week 8 growth photo 56-1, there's a high nitrogen toxicity observed! After that, your plane went into a tailspin! Watch what's happening with your girl! It's all likely due to high pH! Many growers here, as I've noticed, love high pH and planes in tailspins! I would recommend reducing your additives by 30%. If there’s very little calcium and magnesium in the additives, then add cal/mag 1 ml/l (for osmosis), 0.5 ml/l (for tap water). 👆 pH 5.8 Good luck, buddy! ✊😇