Hey there piusmaxis, you're seeing the signs of water mold on the roots from overwatering. You can tell from the puffy space between the veins of the leafs and the wrinkles . What happens is if you don't have a strict enough wet dry cycle then you can get such issues. Alga grow is also a problem for this. Try to increase the zyme and decrease the kelp extract. Of you do this the enzyme should break down the problem roots after a few waterings . Then the plant will recover. But the main issue is overwatering so be extra careful to let the medium completely dry before watering again. Hope this helps ! 🚀