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Thread: New RO membrane

  1. #1
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    New RO membrane

    I'm in Ottawa - where do you guys get your RO membranes? I have a cheap RO unit that I bought from aquasafe (Maximus II). It has lasted seven months making about 100gallons or more RO water a week. (using cold softened well water with an RO booster).

    Reading online I might have ruptured the membrane. I'm going to check its position first. It happened after changing all the prefilters and sediment filter before the RO booster this week. I'm getting a ton of product water but almost nil waste water. If I open it up for more waste water the pressure drops to 20psi.

    So if I need a new membrane where would I get a new one?

    And do you know how the membrane ruptured. TDS was 004 when I changed everything this week.

    Thanks everyone.

  2. #2
    liv
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    Former Moderator liv's Avatar
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    I got my last kit from our sponsor Marinescape... I'm not sure they sell the parts or kits only.. best would be to call them.

    moving.. so temporarily out of SW :b8:
    planning next tank, possibly 60x30x20 on 2x plasma.
    updated: 2011/05/30

  3. #3
    ijo
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    I'm pretty sure Marinescape, Ottawa Inverts or Aqua Valley carry these items in stock.

    IJO

  4. #4
    Former Moderator a4twenty's Avatar
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    to properly asses the membrane, do a comparison between the TDS of the incoming water and RO output. 4ppm isn't that bad, depending on what your incoming is, quality of membrane, pressures and temperatures.

    are you running a DI stage??
    `

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  5. #5
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    Thanks everyone. I'll test TDS before and after. It wasn't that bad if I recall 130-175 or something like that.

    I am running DI also but didn't change the DI resin yet. I wanted to see what changing the filters would do first and it looks like I broke the unit.

    I'll post the numbers later. I'm going to open the membrane case and check the position and see if that helps the waste water. If not I will have to replace it. I'm not sure what causes it to rupture. Its hard to find relevant info with google.

  6. #6
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    Okay tested all my water:
    Wellwater is 160TDS
    TDS of the RO water now is 005

    Still no waste water at all at 40 or 60 PSI. I could do more but not sure what the impact is of no waste water on the RO unit.

    Any ideas what is going on? We checked the position of the RO membrane and it seems fine.

    And the DI resin does need changing for sure. I didn't do this just now. I'll do this once I figure out what is going on with the RO unit.

  7. #7
    Former Moderator a4twenty's Avatar
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    thats ~ 97% rejection rate, which is fine.

    there is 0 waste water coming from the unit or just less????

    changing the two pre-filters ( micron / carbon ) will boost the output of the RO unit but you should still have waste water.
    `

    120S RR tank with 60G basement sump / fuge

    Return Pump: Little Giant 4-MDQX SC
    Water Movement: MP40W, Seio 1500, (2) Hydor K4's
    Lighting: 400W SE MH with 10K Venture
    Skimmer: Euro-Reef RS250 with gate valve
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  8. #8
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    There's nothing wrong with your membrane. Perhaps your flow restrictor is plugged. With my booster pump running, I can hear the water whistling threw mine. If it can't be fixed, purchase a new flow restrictor that matches your membrane output and you should be good to go... Also purchase a flush valve kit, if yours doesn't already have one.
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  9. #9
    Senior Member pt109's Avatar
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    Have you been regularly flushing (back-flushing) the RO membrane? I normally flush mine for about 15 min. per week, when I'm doing a water change.

    HTH
    Man cannot live on bread alone --
    He must also have his peanut butter

  10. #10
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    If I open up the waste water restrictor a ton of waste water comes out but pressure drops very low - 20 or less. The waste water is coming out in drips - and very few - not a steady stream of them.

    I have another flow restrictor right before the RO unit. It is normally almost all the way open because of the RO booster pump. I'm on a well with very low pressure (<20). Maybe this is where I'm messing up. Uhoh. I'll play with this and see if anything changes.

    I have a lot more to think about and look up now. I'm impressed with all the replied I've received!

    I'm really glad to here I don't have to run out and buy a new membrane.

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