Here are the instructions of how to change the Membrane Filter on your Pure Blue Reverse Osmosis System: 

1. The first step is to shut off the water supply to your system.
a. Locate the shutoff valve for your feed and tank and turn both valves off.
2. Next, release the pressure in the system
by opening the spigot and let it drip. Once the dripping has stopped, close the spigot.
3. Now you’ll remove the old membrane.
a. First, remove the drain line attached to the membrane filter.
b. Then unscrew the membrane a half turn, and push the small collet in while pulling the drain line out simultaneously. Finally, unscrew the membrane filter until it is completely out of the manifold.
4. To Install the new membrane, place the new membrane in the slot and tighten counterclockwise until it is hand tight.
a. Then, unscrew a half turn and insert the drain line.
b. Tighten again counterclockwise until it’s hand tight. Now you can open the spigot.
5. Once the membrane is properly installed, you will begin the flushing procedure.
a. Start by turning the feed valve on.
b. Once there is a thin drizzle from the spigot, turn it off. Now wait 10 minutes, and check for leaks. If you see a leak turn the shut off valve off. If there are no leaks, it’s now time to begin your final flush.
6. Final Flush
a. Let system run open for 10 minutes, you will see a thin drizzle from spigot
b. After 10 minutes, close the spigot and open the tank. Make sure to check your cabinet for any excess moisture. If you see anything concerning, simply turn the valve off and give Dupure a call at (877) 534-5837.
Otherwise, your final flush was successful and Your Pure Blue Reverse Osmosis system is ready to be used again.