My vote goes to slowing it down.
The filter floss would allow for a faster flow, but would clogg quickly.
Others will dissagree with me, but in this case, I don't think there is a too slow. The longer the water has time to contact the media the more effective it is. You have to find a balance of enough flow to actually make an impact on your total water volume, but not too much where you are flushing water through, and no filtration has time to take place.