Ok, let me tell you guys something. Have you ever seen how an actual "flush is done"? All that happens is they suck it out, fill it up, turn it lock to lock, suck it out, fill it, turn it lock to lock, do that a couple more times. and you save yourself about 80 bucks. when you turn it lock to lock, it agitates up all the old nasty fluid. it works really really well, i own a shop and we do it alllll the time.