like this,depending on stage of growth say seedling,i exchanged air and nutes once a day,then early veg,once a day,middle of veg1 to 2 times a day,flip to flower start with twice a day,then the show really on,could be up to 4 times a day,the coco and runoff just drain out keeping the coco moist,you are exchanging air and nutes,the plant only takes what it wants,so you very well could be just wasting feed ,but you arent wasting air movement if you got me,this is the reason if i do another coco grow it will at the least have a drain to waste table,at the least ,but a flood and drain would be much better.
so your thinking the roots are just setting in water,nope all that ran out and the air movement dries the coco and as it does still get air to roots the nutreint are in the coco,thats important and reason for so much drainage to get all salts from last feed out,even if you flood the table and nutes are being sucked up threw the cup when the table drains it comes right back out