I would not flush until you understand fully, the process. I personally don’t ever flush, and don’t believe it helps pre-harvest. Flushing is to cleans buildup in soil and media. If there is no buildup, there’s no need to flush.
I believe the teaching of flushing (for taste, or pre-harvest) is way over taught, as proper feeding should be taught in its place.
Some use fading technique, for pre-harvest, which may include a flush. This may speedup cure times, but at the risk of yield size. To me, it’s not worth doing, as chlorophyll (the reason for chemical taste) will break down regardless, over time, with proper cure.
Chlorophyll take time to break down. If you don’t flush, and continue to feed, the more chlorophyll will be remaining, and more time will be involved with breaking it down, after harvest.
Chlorophyll has an amazing history as it invaded the cells of early life. You can almost argue it’s a lifeform in itself, as it has its own DNA, separate from the plant.
…but as for watering, yes, continue and do not stop.