NiceCrits

@Herikus, I look forward to seeing the progress. It's a good idea to check the PH of the water. Mine is around 7.0 and when I add the Biobizz nutes it raises it to 7.2 Previously, I used citric acid to lower the PH to 6.2-6.3. However, if you're using a reservoir, it doesn't keep the PH lowered very long. Thus I switched to Phosphoric Acid. It's a longer-lasting buffer and also adds nutrients. Good luck!

@Treesus01, I also like their products. However, Fish Mix smells and growing with CO2 in a tent requires adding additional P and a lot more K. I think for my next grow I will go Coco Coir or Hydroponic (which is expensive to do right).

Hallo from Berlin! I have grown a few Medusa F1's, including in CO2 and high PPFD. I am using BioBizz as well. A little bit of light burn on the tips is okay... Your Medusa F1 is yellow at the tips, including the lower nodes. Usually with light burn, it's just the top nodes and they get crispy/brown. This looks like it could be nutrients. Check your soil runoff PH and EC. If you don't have a meter, you can find cheap combo meters on Amazon. If those are in normal range, it's probably a hunger for Potassium. If it is a nutrient problem, don't overreact :-) Fixable.