* Turn off the feed water supply line valve to the RO system and the valve on the water tank.
* Open the RO faucet and allow the pressure in the system to bleed off.
* Disconnect the tubing from the membrane housing cap by pushing down on the small ring where the tubing connects to the cap.
* Remove the membrane housing cap by turning counterclockwise.
* Use pliers to remove the used membrane if necessary, then insert the new membrane. The o-ring end goes in first until you feel it seats securely into the membrane housing.
* Replace and tighten the membrane housing cap. Reinstall the removed tubing to the appropriate fittings.