This Fluval FX4 Canister Filter Media Upgrade Bundle includes SEVEN items: the Fluval BIO-FX Biological Media; Fluval FX Ammonia Remover Pads (3 Pack); Fluval FX Phosphate Remover Pads (3 Pack); Fluval FX Nitrite Remover Pads (3 Pack); THREE Inland Seas 6 oz Activated Carbons; & a Towel. The new Fluval BIO-FX Premium Biological Filter Media, 5L (A1459) has a deeper pore structure allowing for more bacteria and higher biological filtration performance than the original BioMax included with the filter. Half of the BIO-FX should be changed every six months. The 5 liter package includes enough media for at least one change. The Phosphate (A262), Ammonia (A259), and Nitrite (A265) resin infused pads help control phosphate, ammonia, and nitrite from building up in the aquarium. There are three of each pad, and they should be changed monthly. Inland Seas Premium Pelletized Activated Carbon is more efficient than impregnated pads but unlike granular activated carbon it is not “friable” (easily crumbled) and will withstand the strong flow in the FX series filters without being reduced to dust. There are three packages of Inland Seas Carbon in this package, and it should be changed monthly.