Hey, please try to take pictures with normal light next time.
Are you feeding any nutrients?
What medium are you growing in?
Carbon filters are for filtering the air that’s coming out of the tent, for air circulation i just place the clip fan near the vent of the tent.
Make sure you have enough drainage holes at the bottom of the container and that it’s lifted a few cm above the surface.
Bring your lights as close as you can without burning the plant ( do the hand test).
Try to raise the temps to 23~28.
And let it dry!
Too much water, i think your plant is drowning.
At this point you should be watering a lot less water and a lot less frequently. As FlowerPower said, the soil needs to have a wet\dry cycle and usually it takes between 2-4days for it to dry
With soil you can grow 4-5 weeks without nutes. The yellowing between veins of the leaves looks like Calcium\Magnesium deficiency so if i were you i would probably try to cut back on nutes and adding CalMag like you said.
Other than her relatively small size she’s looking pretty good imo.
U should make sure your lights aren’t too close\far away from the canopy.
Good luck :weed: