I have yet to actually buy anything extra for a refugium with the exception of lighting. Typically I use an extra deep sandbed and buy about 50 pounds of base rock (55 gal fuge for my 75 gal). I just plumb it inline with my sump. then add gracileria. I am using 2X40 Watt No lighting on 24X7. Xenia and colts and gracilera and calurapas have filled the rest of the tank.