This is the filter set for Aquarium Reverse Osmosis Systems. We recommend changing these filters every 6-12 months for the best quality of water.
The set includes:
(1) 1 Micron Sediment Filter
(1) .5 Micron Carbon Block
(1) DI Color Changing Resin cartridge
If you are needing to replace the membrane too, which should be changed every 3-4 years.