They take them up at night and day,im not sure how long it takes, i know my aero will show sign of what ive just done to the plant a lot faster than soil will. So i guess it depends.
There is tons of info, but I think during Day hours Foliage and Nitrogen (N p k) take part in growing while at night hours pistils form from the plants daylight activities and Phosphorus or more of an (n P k) trade takes place.
They take in water and nutes and co2 and give off oxygen during the day to make sugars or clorofil///at night they take in oxygen and give off co2 and use the clorofil or sugars they produced during the day to grow.