Why are these girls not happy af??? Really appreciate the advice

I have had this exact same problem for 5 grows, always trying to correct it. It only happens on my tent where I have an irrigation system and a good light. Doesn't happen in my low tech closet. I find that it is nutrient deficiency due to lockout, because of overwatering and high EC feeds. You overwater, the plant can't take up nutrients and they get stuck in the medium, raising the PH over time and making it even worse. It starts slowly and ramps up after a while, doesn't it? I found that this helped: I lowered my watering amount for every 3h to have no runoff and I still turn on the pump manually once a day to let it run off a bit. FLUSHED until the ph and ec levels were adequate and been monitoring the output. It seems to have helped. Next grow I'm increasing my perlite so I don't run into overwatering issues. Let me know if you fixed it!

In my opion you over water them check your roots also when you water them water them well then do it again only well you see soil is dry a lot overwater is much worse than dry bone soil

Could be overwater could be ph problems propably too high or not enough nutrients

I believe it to be light burn. I did some research and discovered a bunch of pictures of leaves that were light burned from LED and many of them were identical to yours.

how many of the plants you have show this problem? are they getting the same nutrition? i call it for a root rot, when the synptoms are this strange and wide usually that's the case... but... you growing on air pot...are you keeping the soil always wet? ph problems? too much nuts? did you check the EC of the runoff? are you following the manufacture guidelines for the lamp distance?

Flush flush and then flush again and then water with Kord strength nutrients depending on your medium pH to 5.8 for Coco or hydro and 6.7 for soil

Many issues could cause this. From PH to Ppms to light intensity to temperature and humidity. If the environment is dialed in, then move onto your light. Make sure it's at its recommended height and your In the proper range for your DLI 'daily light intake' for the stage of growth your in. Once that is assessed then check your runoff ppms. Always water enough until 20% runs out the bottom. Check that with a ph ppm meter. If you are 200ppm or more "less" then tour input ppms then you are deficient and need more food. If you are 300 or more ppms "more" then your input ppms then you are heading towards nutrient lockout. Once you make sure your environmental issues are good. Your daily light intake is good And your PH and PPMs in runoff are good that should fix your issue. Please consider selecting me as the answer so I can be entered for a chance to win grower of the month contest. I would truly appreciate it growmie. 🙏

Why do you have so many plants? And what area are you using for the 80 plus plants as its not going to be easy looking after them

Do a diary of what u feed and how u feed when u feed your light your temp everything and maybe someone will help you

Light looks too intense and you may be experiencing a ph issue or improper diet.

@Asnoriu What your recommendation to do?

I also thought of an magnesia deficit… I have now increased the distance between the lights and the plants to 80cm. Will get some magnesia as well

Thanks for the assessment…the ph in the water was always 6.1-6.2. I use osmosis water and add PH-up after I add the nutrients. PH of the soil is between 5.5-6.5

Too low ph and you burned them with food, i see magnesium issue too. Maybe lights added, but they cant burn to that level, i had 1.3 KW setups blasting 20-30 cm away from canopy - never nothing even close. When once i loaded 4.3 ph and big feeding, i had even worse look, but a lot similar to yours. Molases adding to feeding did some burn too. But i would bet on too low ph in.

Thanks for the reply. Temperature in the room is around 28 degrees with the lights on and 22-24 degrees during night

I would say you are correct. Light to close and to much heat. Bleaching from to much light and leaves turn up and look like a canoe. To much heat.

Grow tent - 240x240x200 Lights: 4 x cretivity 720W - dimmed down to 400W Distance between plants an lights is around 50cm 70 plants - clones bought at greenhouse Thailand (Velvet Moon, Persian Pie, Alienz) Plants age: 5 weeks Pot size: 2 gallons air pots (15x20cm) 18 pants on 120x120 (400W for this amount of square and plants) Fertilizer : greenhouse hybrids, greenhouse calcium EC: 1,4 (like greenhouse recommended) PH: 6,1-6,2 Water temperature: 20-22 degrees