Started training the 3rd toppings. Noticing some ugliness on a few of the older leaves which I think is from lack of water. Also some yellowing leaf tips that I think is light burn. Moved light back to 18 inches. Removed all lower growth at the end of this week. Co2 has been lower this week since it's been warm and the heater hasn't been running, more normal levels of 900-1000ppm when I'm not in there.