Second one? The first second. Is that the confussing part, or jsut me in general? <g>
IF you are in Deep Water C? (bubblers) you begin flushing your plant instanly. In dirt you have to get the neuts out of the dirt firts. Then you will start flushing the plant.
Just saying that in mydroponics you should be able to flush less time then in dirt. So, once you know when you plants get ready for harvest you can flush the shortest possible time. If you start to flush to early you could reduce your quantity/quality.