First, turn off the water supply to the system—look for a little valve or knob under the sink. Then, open the faucet to release pressure (it might sputter a bit, which is very dramatic and deeply satisfying). Unscrew the filter housings with a wrench (most come with one, or use your bare hands if you’re a monster). Discard the old filters, rinse the housings with plain water, and install the new ones. Pro tip: Put the o-rings back on before you curse yourself for losing them.
Reverse Osmosis Filtration System Maintenance at Christian Liao blog
For the membrane, you’ll need to disconnect a few tubes—take a photo first so you don’t play “guess the plumbing” later. Pull out the old membrane (it’s a white cylinder), push in the new one gently (it only goes in one way, like a USB, but actually works), and reconnect the tubes. Turn the water back on, check for leaks, and run the system for 10-15 minutes. The first batch of water might look cloudy—that’s just air bubbles, not a ghost. You’re good.
