Here are the instructions of how to change the Pre and Post filters 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
a. by Opening the spigot and let it drip. Once the dripping has stopped, close the spigot
3. Then you’ll remove the old filters
a. by turning each filter clockwise until they are clear of the manifold
4. Now it’s time to begin the flushing procedure
a. First, temporarily install the first new filter in the Post filter slot and open the spigot
b. Then, open and close the tank at 3 second intervals until the water runs clear
c. Once the water is clear, close the tank, and wait for the water to stop dripping
d. Once the dripping has stop, turn off the spigot
e. Now, remove the newly flushed filter from the Post filter slot and reinstall it on the Pre filter slot
f. Install the second new filter on the Post filter slot, and repeat the flushing process, leaving the spigot on when done
5. After you complete the flushing procedure, you’ll pressure test the system
a. At this point, both filters should be installed, and the spigot should be on. Now you can turn the feed back on
b. Once proper flow has been confirmed, turn the spigot back off
c. Let the system build pressure for 10 minutes, while continuously checking for leaks
d. If no leaks are detected, you can open the tank and begin the final flush
6. Final flush
a. Let the tank fill for 1 hour. After the tank has filled up, open the spigot and completely drain the tank.
b. After the system has drained, turn the spigot off and let the tank fill up again
c. Your Pure Blue Reverse Osmosis system is ready to be used again