K1 is incorperated in my setup. I have a 120ltr per minute pump turning over 125 litres of k1 and 25 litres of bio chip. working well for me. I use 2 200mm ceramic air disks to move my media.you can see my sump at approx 1.07 mark
http://www.youtube.com/watch?v=Wi7GsiBodQk
Hope this helps...