The A/C fan is most likely not powerful enough to push through a carbon filter efficiently. To keep even pressure in the tent you’d need an inline intake and exhaust fan with the same flow.

What time of the day was this picture taken? The droopy leaves could be from over-watering, stressing the roots preventing nutrition from being available. They look hungry but is it because they lack nutrition in the soil or are the roots damaged making available nutrition in the soil unavailable? Tell us more about your grow.