I use 20ML of sunlight soup at the beginning of flushing to help to salts and soil- than straight-ph-adjusted water from their on.
Its really depends on how much plants ya got man. Think about it for a sec, are u going to flush 3x the planter volume with water on multiple plants? I have two flower rooms. Each with 32plants (2x1000 and 2 600) in each room. Even tho each room flowers at different times-I am not going to flush 3x the volume on 32 plants. It would take forever.
I am not bashing the idea but I know enough peeps that are involved with larger shows and they use simple, old school style that works great!! If u have a few plants in the closet-maybe try flushing 9 gallons in one. Anyways, just trying to light'n ya up about the misconception on flushing!!
Again MCpurple, not trying to say your info is shit- I do it this way, and it works also well. Good luck 2 the both of ya