thank you for your availability. I'll tell you right away that I don't buy random things. I fertilize my plants with the complete PLAGRON organic line: Grow/bloom algae etc... I always check the pH of my water at every irrigation, furthermore the soil I put is rich in earthworm humus, guano, perlite and a good dose of Mycorrhizal fungi right from germination. I detached that leaf immediately after both water and heat stress (the cooling system turned off while I was away, reaching 37/38 C° with 20% humidity for almost 36 hours! It's a miracle that they didn't die, you can see that they are F1 genetics. ☺️. in my opinion that is a light/heat damage in a dry environment. as you can see now they're back to being nice and green. don't you think?