Super urgent, 1st time grower, marked previous as resolved accidentally, issue persistent

1,5l water for 37l pot? better invest in a solid moisture meter next.

get a humidifier. There are no 'natural' ways to fix your RH. You might be able to bring it up a few percent doing some DIY stuff, but it'll be insufficient, gauranteed... so small it'd be wasted effort. You need a humidifier. They are not that expensive. You'll need one large enough for the room that the tent exchanges air with. Adding moisture is WAY cheaper than removing it, so this is a much better context than the opposite problem. Strongly suggest avoiding the vaporizer type -- that's what leaves the grimy white layer of dust on anything when in use. A wick-based humidifier will not do that, but you do have to buy wicks... if you use clean water and the bacteriostatic solution you can maximize life of a wick. Your watering habits sound flawed too. You do not whimsically choose volume of water to give. You give what is required to fully saturate, wait for appropriate dryback, and repeat. If not doing this, you are doing it wrong without question. If it is soilless, you also need 10% runoff religiously. Bet that takes care of the droop, because the medium in that picture looks dry AF. With coco, when the top starts to turn color (after full saturation), it's usually a good time to re-irrigate. Weight of the pot is an even better trigger. If you consistently irrigate at same loss of weight, it will require a consistent volume of water - you learn the volume in hindsight. I would fix this habit before tweaking formula... some problems may solve themselves. assuming it is soilless: if you stick to 10% runoff avoids buildup. This means any symptoms you see are 100% fixed through adapting formula. You can see my vege and initial flower formula in my 'mint' diaries. Germ week and the week before or after flower phase starts.. somewhere in there, lol. fuck AN's formula. Mimic what crop salt, mega crop, southern ag, masterblend, jack's, kosher-somethign-or-other and others do. It's based on existing knowledge instead of some amatuer marijuana grower re-inventing the wheel in his garage and sellings over-priced fertilizer with cartoon graphics to attract children like sugary cereal brands, lol. Far better starting point, imo. As with most things, you do need to adjust the formula to jive with your local variables. If you fix the VPD, you may need to adjust further.

Ja, da ist etwas viel N drin aber ich glaube nicht, dass es toxisch ist - die Blätter zeigen auch noch keine Krallen. Das ist nur etwas überfüttert. Ich hatte in deiner vorherigen Frage ja geschrieben, was ich davon halte.

Nitrogen toxicity, not a "pH spike".............long term over feeding is the cause. Plain water for approx 10 days, no fertilizers at all, then when you resume feeding, start with half strength/frequency as to what you were doing previously. Damaged leaves will not recover, but new growth should be ok. Also, make sure you water to run off each and every time you irrigate, this is vital for long term soil health.