Here is a helpful filter media thread for newbies. I used Bio Chem Stars too for my XP 3. I don't know if one box is enough but the XP3 instructions said to use Bio Chem Stars and Ceramic rings so I one try of bio chem stars and another try filled with ceramic rings.
http://www.monsterfishkeepers.com/forums/showthread.php?t=88677&highlight=scrubbies
http://www.monsterfishkeepers.com/forums/showthread.php?t=88677&highlight=scrubbies
