LiquaGen Replacement Set for 7 Aquarium Reef Reverse Osmosis Water Filter System | Sediment/Carbon/GAC/ 2 Pounds Color Changing DI This is the exact replacement set for the 7 Stage Aquarium Reef Reverse Osmosis Water Filter System. The replacement set includes: 1) One 5 Micron Sediment Filter. 2) One GAC filter. 3) One 5 Micron Carbon Filter 4) One 2 Pounds RO/DI color changing Resin Deionization.