I finally got my 30 bags of Flourite. I decided to give it "no-rinse" a go. I just poured them in, filled 1/2 tank, and drained a couple of times. To my surprise, it worked pretty well. Maybe I got them right from the box, so I got much less dust?
One thing I have to complain though, the lot I have got were very damped, and there are one or two soft clay ball sized at least an inch or two in each bag.