Recharging Storage Tank Procedure

I have recently ordered replacement filters for my Microline T.F.C. 25S RO water filter, and still am receiving a VERY small amount of water….
Can my current tank (which is what I now suspect is the problem), be recharged, and how would I do this?
Or do I need to replace the tank?
Is the RO4B tank compatible with my MicroLine RO system?
The tank and RO system are currently under my kitchen sink.
Is it better idea to get a tank (if I need to replace it) with the replaceable bladder?
Thank you for your assistance with these questions.

Here’s the information that might be helpful.



  • When you turn on the RO spigot you noticed small water pressure coming from the storage tank.
  • When you turn on the RO spigot, only a quick burst of pure water comes out of the system, and it slowly dies down to trickles.
  • When you turn on the Reverse Osmosis spigot in the morning, you only can get less than one gallon of purified water.

  • If the above problems are there, you may wish to recharge the reverse osmosis system’ TANK, because the storage tank should contain about 7 psi of compressed air inside the tank when empty.
    The storage tank has a water bladder inside, and it is surrounded by compressed air.
    This way, when you turn the spigot on, the compressed air would compress or squeeze the water bladder to force the pure water out of the tank.
    When the tank is full, the tank pressure would reach about 35 to 50 psi depending on the pressure of the feed water (before it’s stored).


  • A compressor or air pump (like an air pump for a bicycle tire)
  • Air Pressure Gauge that would be able to read less than 10 psi
  • Adjustable wrench or 9/11″ wrench
  • STEPS:

    1. Shut off the feed water to the Reverse Osmosis system
    2. Turn the spigot ON to allow pure water to get out of the RO system, until it stops (you may save the RO purified water if you wish)
    3. Check if there’s still water remaining in the RO storage tank by lifting the tank.
      – If the tank feels heavy, you need to recharge tank… continue the following steps.
      – If the tank feels light, you don’t need to recharge the tank at this moment.
    4. Locate the air valve on side of the storage tank. It would look like an air valve on tires.
    5. Use the air pump or air compressor to get air into the RO tank. While pumping air, keep the spigot on, so all water still inside the tank would be purged.
    6. After all water is drained, use an air pressure gauge to check tank pressure.
    7. When empty, the RO tank should have about 7 psi of pressure.
      – Add or Release Air as necessary.
    8. Turn ON the feed water valve, and turn the spigot OFF to allow tank to refill.
    9. Unless you don’t know by now… You’re done!

    For a 3-stage Reverse Osmosis with 10 Gallons Per Day capacity, it would take about 8 hours to fill the RO tank.
    For a 5-stage 25 Gallons Per Day unit, it would take about 4 hours.
    A 35 Gallons Per Day system would fill the tank in about 3 hours.

    If after running the system for a few days, the problem returns, i.e. one of the problems mentioned above, then you may consider replacing the tank to a new one.
    There’s no difference on which tank you choose. Any reverse osmosis water filter system, that has the same connection, should be compatible with any tank.


    1. Bob Bell said,

      June 25, 2007 @ 1:27 pm

      What are the procedure for changing culligan water filters (reverse osmosis type)??

    2. admin said,

      June 26, 2007 @ 10:47 pm

      Some Culligan Reverse Osmosis units are different than the standard. However, the How To change Reverse Osmosis Filters might be of help here. It also has a link (at the bottom of page) to Membrane Changing procedures.

    RSS feed for comments on this post · TrackBack URI

    What’s on your mind