Servus Mateโ๏ธ,
because there are a lot of mobile Nutrients, it makes perfect sense to have the water pH'd. U wanna get your pot emptied. I also add some enzymes to brake up the rest of the usable bio material for the plant. Personally I'm not a big fan of flushing. Don't get it why I should stress her so massively to the end. Keep going, ur ladies look brilliant.
Servus, Oim.