Growth looks good, but hard to see if there are any deficiencies in purple light. Try turning lights off and using flash. It will show them in their true glory
Purple.............and as if they MAY be experiencing a bit of stress.......either light, heat, wind......
Your plants need a drink, and your Three-Way Meter agrees. They look big and healthy. Can't tell everything without color, as was said. For real that meter's like an essential non-essential tool for indoor growers. Use it all the time, especially for light readings as they grow.
You probably want to make that more stable. The nerds agree that a 10 degree swing is ideal. Small oscillating fans and/or an exhaust fan can help. If odor isn't a concern, you can also just open up the tent flaps at the top while the lights are on, if you're running LEDs. The tent is for the dark, not the light. You're going to want to get oscillating fans eventually for when your plants put on weight and start to bud. You don't want too much condensation forming on the buds, it causes them to mildew.
those CO2 bags.......from what I understand.......are lacking in what the produce.......and depending on how you have your vent system set up.........might vent out all the "beneficial" CO2 anyway......
Just keep the lights at a height that the Three-Way Meter says will give them about 2k lumens, but not so much that the leaves start pointing towards the ceiling. Try to figure out a way to keep your grow a little bit cooler during the "day" and/or a little warmer during the "night." Oh, and if you haven't already, water your plants. You're doing great.