Results 1 to 8 of 8
  1. #1
    Senior Member
    Join Date
    Jan 2004
    Posts
    373

    Changing membrane size?

    Is it possible just to put in a bigger size membrane to increase your water output? I have a 50 or 60 gpd membrane, can I just put in a different size? Also how can I take out my membrane to check the exact size, just shut off all the water coming into the unit. Is there any problems with taking it out and putting it back in? Thanks

  2. #2
    Senior Member reefmutt's Avatar
    Join Date
    Oct 2003
    Posts
    1,770
    Shut off the water coming in and give it a minute for the pressure to fall, then simply unscrew the head of the membrane housing. You may have to use pliers to pull out the membrane, it can be re inserted and used without any problems. Membranes are all standard, pretty much, the size doesn't really change, so you should be able to simply pull out the old one and put in a new one.
    NOTE: new membranes are impregnated with an antibacterial to keep them fresh, so let it run for a couple of hours before you start collecting water for the tank.
    When changing membranes, a problem arises with the rejection rate of a new membrane as opposed to the old one.
    On the waste water line of r.o. units, usually right at the housing, is a restricter in the hose which slows down the water exiting the waste water line. This restrictor was cut to a length which corresponded to the production rate of the original membrane. You want to have a 4 to 1 ratio of waste water to good water to have a membrane working at peak efficiency. So, if you change membranes you will have to measure the outputs of both your waste water and good water to see if the restrictor is allowing the proper amount of water to pass through the housing. This restrictor is just a smaller diameter tube which is inserted in the line- the longer the little tube is, the more of a restriction and shorter- less restriction.
    The restricter is on the waste water side to create some back pressure to force some of the water coming into the unit through the r.o. membrane and then allow the rest to exit via the waste line. I'm not exactly sure where you can find replacement restrictors- maybe from the membrane manufacturer or from an r.o. unit maker in the hobby like Kent.
    Maybe you could just find a small 3/4 inch valve and put it on the waste water line and adjust at will, instead of having to cut a restrictor down to the right size.
    I don't know if your membrane will have any markings on it as to gph etc.
    Did this answer anything or just make it more complicated?????
    Matt.

    Old system torn down to make a playroom.. planning a 62x42x28 high

  3. #3
    Senior Member
    Join Date
    Jan 2004
    Posts
    373
    I just took out my mebrane cause it was shot. So will my system be okay empty for a couple of weeks? I have to wait till next payday.

  4. #4
    Senior Member ALRHA's Avatar
    Join Date
    Sep 2003
    Posts
    2,842
    I know Marine Depot sells the restrictors based on the membrane output you have.
    Albert
    My Photos

  5. #5
    Senior Member reefmutt's Avatar
    Join Date
    Oct 2003
    Posts
    1,770
    do you mean the pre filters when you say system? if so,then yes they will be fine.
    Matt.

    Old system torn down to make a playroom.. planning a 62x42x28 high

  6. #6
    Senior Member
    Join Date
    Jan 2004
    Posts
    373
    I just put in a new membrane. Do I have to drain out the first batch of water it makes, or can I use it right away?

  7. #7
    Senior Member reefmutt's Avatar
    Join Date
    Oct 2003
    Posts
    1,770
    You should let it run for an hour before collecting the water, to flush out any preservative in the membrane.
    Matt.

    Old system torn down to make a playroom.. planning a 62x42x28 high

  8. #8
    Member EmilyB's Avatar
    Join Date
    Nov 2003
    Posts
    37
    I put in a 100gpd membrane into my 75gpd unit and it increased the performance for me.

Similar Threads

  1. Where can I buy an RO membrane?
    By klkelly in forum Lighting, Filtration & Other Equipment
    Replies: 4
    Last Post: 08-08-2010, 03:00 PM
  2. New RO membrane
    By klkelly in forum Water Quality
    Replies: 24
    Last Post: 09-02-2009, 11:09 AM
  3. Old RO membrane
    By zeke in forum Just Getting Started
    Replies: 4
    Last Post: 09-28-2005, 12:01 PM
  4. fish size vs tank size?
    By volitan in forum Just Getting Started
    Replies: 43
    Last Post: 10-24-2004, 09:45 PM
  5. Membrane and TDS?
    By Gools in forum Water Quality
    Replies: 3
    Last Post: 06-25-2004, 03:23 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •