The natural phenomenon of barometric pumping, sometimes called "soil breathing" or wind-pumping, is a crucial mechanism for soil aeration where oxygen is driven into the soil while gases like
carbon dioxide are expelled, primarily driven by fluctuations in atmospheric pressure. This process, along with diffusion, replenishes oxygen levels in the soil, which is essential for the respiration of plant roots and soil. Your grow looks so big, there is no tent, therefore you cannot replicate barometric pumping unless you have a negative pressure to simulate high & low.
The physical properties of water make it a "lockout" mechanism when the medium is oversaturated, because oxygen diffuses 10,000 times slower in water than in air and 320,000 times slower in soil saturated past a point. Gotta make sure by time đ night comes the medium is in a sweet spot for oxygenation and the ambient night air has adequate "space" (lowerr RH%) for more moisture to be added all night long, needs to remain controlled. Failure to do so will gradually overtime if water is not moving fast enough or is getting trapped anywhere in those pots its just a matter of time.
Keeping close tabs on ambient humidity day and night during the flowering period is crucial for indoor plants. A thick, shaded canopy restricts airflow and reduces evaporation of the medium. In this phase, high relative humidity (RH) not creating an adequate wet-dry cycle can slowly start to break down the entire energetic process, which is often the problem around mid-flower. The transition of microorganisms from aerobic (oxygen-rich) to anaerobic (oxygen-deprived) conditions results in a significantly slower breakdown. Plants run on 10%-20% energetic potential, acids are released in the form of lactic acid, eventually skewing ph acidic. 40% of all carbon a cannabis plant captures is exuded into the soil to feed Micros, this slowly increases CO2 in mediumand moisture retention with it as time goes on. If you are also delivering nutrients organically, then the microorganisms will also directly compete with the plant for oxygen at a higher rate than compared to synthetic delivery. Very very common to see 4th week of flower onwards a complete breakdown of oxygen. Slowly, over time.
Negative pressure is what pumps fresh oxygen in and CO2 and nitrogen out of mediums. If environmental conditions are not "moving" water fast enough from mediums to atmosphere promptly then it becomes a slow slog of breakdown, yellowing, and various symptoms for whatever process breaks down first will present. Generally recommended you know what your doing prior to running such a massive grow. Pretty hard to imagine anyone having spent that much money to setup yet have no clue when or why to water. Seems a little far fetched, plants don't look droopy, they look like how they are supposed to, tips say EC of medium is close to where it should be.
Your doing something right, impressive looking plants, just gotta keep everything flowing to keep growing, very best of luck, she looks amazing.