Still curled down / hanging leaves

Yeah, I will wait for the plants to show signs of missing nutrients before adding more. The provided schedule of Hesi doesn't seem to be appropriate as it only depends on amount of water and not considering size or number of plants. PH is at 6 to 6.5 according to two different test kits, that should be fine. I can't see the problem with watering/oxygen as I said, just few roots are hanging into the water the others are just air roots. I will stop top watering them (only did it once this week thou) to reduce that vector of problems and reduce light a bit more :D

Just looks like your medium is getting too wet or your light is too close. The roots aren't getting enough oxygen is my guess though.

Cheers bro, yeah I am no hydro pro either, in fact it is the first time for me growing Cannabis and hydro lol Neither of the plants are in direct contact with the water surface, but just few roots are reaching into the nutritious solution, so it is up to the plant to soak its water needs upward. Both plants are having roots that don't touch the water surface, so the plants should have enough oxygen too, besides that an air pump is running inside the reservoir pumping oxygen into it, so it doesn't seem to be the most plausible cause of the problem. I have been top watering both once this week, so I guess I shouldn't do that unless like super necessary :D Half of the grow lamps aren't hanging right above the plants, so that number maybe is a bit misleading. Anyway I will try to further reduce the individual stress due to light and extra watering.

Make sure your ph right. Use a calibrated tool. Next back off nutrition. It is too strong for baby plant. The amount of green in leaves says too much nitrogen. So I would imagine p and k are up high to. If it's a photoperiods you have time to veg once its growing. Good luck and happy growing 🌲🌲🌲👊