Leaves turning a yellowish color

seems to me to be lacking of magnesium. if the tips of the leaves are curling upwards, there is a lack of magnesium. if the tips of the leaves are curling downwards it is lack of potassium.make a flush to clean and remove mineral salts from the substrate and applies a good dose of calmag. I wish you luck for your grow mate 💪🍀

After looking at the pictures in your diary, I believe you have nutrient burn, specifically nitrogen. The slight clawing of the leaves, 90 degree angled tips and browning at the tips of leaves all point towards nitrogen toxicity. https://www.growweedeasy.com/cannabis-plant-problems/nitrogen-toxicity

@Septooth Hi mate I think you need to use more Calmag as that does look a little like a magnesium deficiency