1st Grow!! Indoor QB Led grow - 4 strain

Hello my guys! So.. today is the end of week 4 since the start of this adventure. The lady’s are doing good. They have some issues (the brown/bronze spots in some leafs as well as burned tips) guess it was from PH fluctuations (just got the ph meter on week 2) but on the overall I think we’re doing good. I was divided between Fimming or Topping, decided to go on topping and it went really well. Most of the plants gained at least 4 new tops and it’s amazing to see the lst results day by day!! I count at least 8 tops on each (for now) except on one of the clones that is still healing, but she will get there. Bought a new extractor too, it’s a cornwell electronics 125mm with 2 fan speed wich helps a lot to control the humidity and temperature levels I’m really in love with this girls, the results and with growing. Such a pleasant activity and I just can’t wait to smoke the results of my hard work and research. Any advice/opinion will be more than welcome. If anybody has a different opinion on what can be causing the spots or the burned tips please let me know!