i think it's kind of silly to flush before flip to flower personally for the reason that the only real difference between most vegetive nutes and flower nutes is that veg nutes tend to have more nitrogen then flower nutes, and flower nutes have more potassium for the most part.. and wtf, do plants magically stop needing nitrogen in early flower all of a sudden even though this period is when they tend to grow the most and fastest?? i'd think not.