Additional Details ------------------------------ Bullet point: STAGE 1 - 1x Carbon Block Pre FilterReplace Every 12 Months|STAGE 2 - 1x RO Membrane TFC 50 GPD Replace Every 24 Months|STAGE 3 - 1x Carbon Block Post Filter - Replace Every 12 Months 2) 5micron carbon filters 1) membrane Filters may need to be replaced more often than indicated depending on incoming water contaminant levels and volume of water being treated.