RO pressure booster pump

Discussion in 'Reef Fishes' started by Pszemol, Nov 2, 2003.

  1. Pszemol

    Pszemol Guest

    "Chimera" <nchimera@yahoo.com> wrote in message news:7afde90.0311051433.221d58de@posting.google.com...
    > Whoa.
    > From what I know about RO, a semi-permeable membrane is used to reject
    > molecules (?) larger than H20.
    > How would low pressure defeat the membrane? Must be the design of the
    > unit(does the source water get around the membrane?) , not the
    > physics.


    I was confused reading Marcs words the same way...
    And if membrane is leaking, it would leak more with higher pressure, right?
     
    Pszemol, Nov 6, 2003
    #21
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  2. Having an auto top off feature is wonderful, but it has to be controllable. If' I have to go out
    of town for a few days, and the switch fails/jams/etc... 30 minutes after I leave, water could
    continue to flow for days until I get back.

    However, making 30 gals of water, then hooking up a switch/float valve to that is a good method of
    protection. Once a week you fill up the resevoir, and then for 7 days you let the resevoir top
    off your tank.

    Marc


    Pszemol wrote:

    > But what you do defeats the purpose of havin automatic top-off system...
    > Is there another way to do the same job without human/manual operations?
    >


    --
    Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
    Business Page: http://www.sparklingfloorservice.com
    Marine Hobbyist: http://www.melevsreef.com
     
    Marc Levenson, Nov 6, 2003
    #22
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  3. Pszemol

    Rod Guest

    >You do not want to know that
    >your floor got flooded when you get home from work / school or whatever. It
    >will become another expense to fix.


    I agree.. nor do you want your tank flooded with fresh water.. Float switches
    in reef tanks can and will fail due to calcium deposit build up and even salt
    creep. If you must use a float switch to control you top off unit, I recommend
    inspecting and cleaning weekly.
    Rod Buehler
    www.asplashoflife.com
     
    Rod, Nov 6, 2003
    #23
  4. Pszemol

    Pszemol Guest

    Assuming the most pessimistic scenario, the switch will fail 30 minutes after you
    leave and you will have 30 gals of fresh water in your tank.

    Maybe the solution is to have to float valves/switches?
    One for regular top-off, and the second and inch or so higher, for safety.

    It would greatly improve your chances of coming home and finding
    everything in order... Both probabilities of switch failure will multiply giving even
    smaller probability of overall failure - at least that is what I remember from school ;-)

    "Marc Levenson" <melev@swbell.net> wrote in message news:3FAA3F09.869A15A6@swbell.net...
    > Having an auto top off feature is wonderful, but it has to be controllable. If' I have to go out
    > of town for a few days, and the switch fails/jams/etc... 30 minutes after I leave, water could
    > continue to flow for days until I get back.
    >
    > However, making 30 gals of water, then hooking up a switch/float valve to that is a good method of
    > protection. Once a week you fill up the resevoir, and then for 7 days you let the resevoir top
    > off your tank.
    >
    > Marc
    >
    >
    > Pszemol wrote:
    >
    > > But what you do defeats the purpose of havin automatic top-off system...
    > > Is there another way to do the same job without human/manual operations?
    > >

    >
    > --
    > Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
    > Business Page: http://www.sparklingfloorservice.com
    > Marine Hobbyist: http://www.melevsreef.com
    >
    >
     
    Pszemol, Nov 6, 2003
    #24
  5. Pszemol

    CapFusion Guest

    "Rod" <rbuehler9@cs.com> wrote in message
    news:20031106074507.05943.00000192@mb-m28.news.cs.com...
    > >You do not want to know that
    > >your floor got flooded when you get home from work / school or whatever.

    It
    > >will become another expense to fix.

    >
    > I agree.. nor do you want your tank flooded with fresh water.. Float

    switches
    > in reef tanks can and will fail due to calcium deposit build up and even

    salt
    > creep. If you must use a float switch to control you top off unit, I

    recommend
    > inspecting and cleaning weekly.
    > Rod Buehler
    > www.asplashoflife.com


    If auto-topoff require, I would hook it up to a resoviour that hold certain
    amount. If any auto-switch / float etc fail, it will just empty the resovour
    only.

    CapFusion,...
     
    CapFusion, Nov 6, 2003
    #25
  6. Pszemol

    Raymond Guest

    "Pszemol" <Pszemol@PolBox.com> wrote in message news:<boc7gd.20c.1@poczta.onet.pl>...
    > "Chimera" <nchimera@yahoo.com> wrote in message news:7afde90.0311051433.221d58de@posting.google.com...
    > > Whoa.
    > > From what I know about RO, a semi-permeable membrane is used to reject
    > > molecules (?) larger than H20.
    > > How would low pressure defeat the membrane? Must be the design of the
    > > unit(does the source water get around the membrane?) , not the
    > > physics.

    >
    > I was confused reading Marcs words the same way...
    > And if membrane is leaking, it would leak more with higher pressure, right?


    As I understand it the loss of purity at low pressure is due to the
    slow rate at which the clean water is going through the membrane. The
    membranes are manufactured with defects. That is why they let a small
    percentage of impurities through. The membrane requires a certain
    amount of pressure to force the pure water through. The impurities go
    through the defects at a much lower pressure. As the pressure rises
    the amount of impurities forced through the defects goes up but not at
    the same rate as the pure water. In other words the defects are little
    holes in the membrane. At lower pressure the only water getting
    through is through these defects. As the pressure rises you start to
    get water through all of the membrane and the pure water then dilutes
    the source water leaking through the defects down to a very low level.
    The lower the pressure the higher the percentage of impurities. The
    membranes are tested and the specs given are at 65-70 PSI. My
    understanding is that at some point, as the pressure goes up,
    impurities are forced through the membrane. This means there is a top
    end limit (prior to bursting the membrane) at which you should operate
    the filter at. If memory serves the optimum limit was at 100 PSI. If I
    had the cash to drop on a booster pump, I would, and I would set the
    pressure to 100PSI. Actually I would probably write the manufacturer
    and ask the question again as this information is several years old
    now....
    FWIW
     
    Raymond, Nov 6, 2003
    #26
  7. Pszemol

    Pszemol Guest

    Yes, it makes sense. I did not consider defects in the membrane film.
    Thank you.

    "Raymond" <rdsmith@intcon.net> wrote in message news:e519c6f1.0311060936.3b56921b@posting.google.com...
    > As I understand it the loss of purity at low pressure is due to the
    > slow rate at which the clean water is going through the membrane. The
    > membranes are manufactured with defects. That is why they let a small
    > percentage of impurities through. The membrane requires a certain
    > amount of pressure to force the pure water through. The impurities go
    > through the defects at a much lower pressure. As the pressure rises
    > the amount of impurities forced through the defects goes up but not at
    > the same rate as the pure water. In other words the defects are little
    > holes in the membrane. At lower pressure the only water getting
    > through is through these defects. As the pressure rises you start to
    > get water through all of the membrane and the pure water then dilutes
    > the source water leaking through the defects down to a very low level.
    > The lower the pressure the higher the percentage of impurities. The
    > membranes are tested and the specs given are at 65-70 PSI. My
    > understanding is that at some point, as the pressure goes up,
    > impurities are forced through the membrane. This means there is a top
    > end limit (prior to bursting the membrane) at which you should operate
    > the filter at. If memory serves the optimum limit was at 100 PSI. If I
    > had the cash to drop on a booster pump, I would, and I would set the
    > pressure to 100PSI. Actually I would probably write the manufacturer
    > and ask the question again as this information is several years old
    > now....
    > FWIW
     
    Pszemol, Nov 6, 2003
    #27
  8. Pszemol

    Raymond Guest

    What I am doing addresses this except that I don't top-off with just
    RO water. I mix up lime water (Kalkwasser) to dose with. I had all the
    same worries. If the float valve sticks and it is connected to an
    endless supply of water or even a large container of water....

    So I mix my lime water in a container. The container has a float valve
    with a mechanical valve that is used to refill the container with RO
    water. I leave the mechanical valve open unless I'm going to be gone
    and not available to check on it or I want to maintain the strength of
    the mix in the container. (which I do frequently) The makeup water is
    pulled from the container with a dosing pump. The dosing pump is set
    to dose at a rate that matches water evaperation + ~10% or so. (This
    allows for varying evaperation rates due to changes in humidity
    through out the year) The dosing pump is plugged into a float switch
    that turns it off if the water gets to high in the sump. The float
    switch is plugged into a mechanical wall timer that turns on at night
    for about 12 hours. This causes the days evaperation to be replaced
    with what ever is in the container (kalkwasser) through the night at a
    slow rate. If I missed on the dosing rate then the float switch will
    turn it off. If the float switch sticks then it still will only add a
    little too much until the timer turns it off for day operation and
    even if the timer were to fail then it still can only add as much as
    is in the container unless I left the valve on.

    Now this is a little different because of the lime water but all but
    the day/night timer would still be applicable and make it quite safe.

    Just my two cents...

    "Pszemol" <Pszemol@PolBox.com> wrote in message news:<bod38j.js.0@poczta.onet.pl>...
    > Assuming the most pessimistic scenario, the switch will fail 30 minutes after you
    > leave and you will have 30 gals of fresh water in your tank.
    >
    > Maybe the solution is to have to float valves/switches?
    > One for regular top-off, and the second and inch or so higher, for safety.
    >
    > It would greatly improve your chances of coming home and finding
    > everything in order... Both probabilities of switch failure will multiply giving even
    > smaller probability of overall failure - at least that is what I remember from school ;-)
    >
    > "Marc Levenson" <melev@swbell.net> wrote in message news:3FAA3F09.869A15A6@swbell.net...
    > > Having an auto top off feature is wonderful, but it has to be controllable. If' I have to go out
    > > of town for a few days, and the switch fails/jams/etc... 30 minutes after I leave, water could
    > > continue to flow for days until I get back.
    > >
    > > However, making 30 gals of water, then hooking up a switch/float valve to that is a good method of
    > > protection. Once a week you fill up the resevoir, and then for 7 days you let the resevoir top
    > > off your tank.
    > >
    > > Marc
    > >
    > >
    > > Pszemol wrote:
    > >
    > > > But what you do defeats the purpose of havin automatic top-off system...
    > > > Is there another way to do the same job without human/manual operations?
    > > >

    > >
    > > --
    > > Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
    > > Business Page: http://www.sparklingfloorservice.com
    > > Marine Hobbyist: http://www.melevsreef.com
    > >
    > >
     
    Raymond, Nov 6, 2003
    #28
  9. Raymond's system is the only way I'd dose Kalkwasser. They have some very nice pumps that will only add
    up to 4g a day (some are designed for less per day, others for more), but the one I liked was $200!

    Using dual float switches will work fine, if you use a small powerhead to feed the water. However, if
    you want to use the Kent Float Valve, you don't have that option. It is a plastic air filled device
    that falls downward to let water in, and as the water level rises, so does the float arm until the feed
    line is blocked. This is the kind many use, but I don't recommend them being hooked up directly to the
    RO/DI. It'll work fine with a gravity driven resevoir though.

    Marc


    Pszemol wrote:

    > Assuming the most pessimistic scenario, the switch will fail 30 minutes after you
    > leave and you will have 30 gals of fresh water in your tank.
    >
    > Maybe the solution is to have to float valves/switches?
    > One for regular top-off, and the second and inch or so higher, for safety.
    >
    > It would greatly improve your chances of coming home and finding
    > everything in order... Both probabilities of switch failure will multiply giving even
    > smaller probability of overall failure - at least that is what I remember from school ;-)
    >
    >


    --
    Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
    Business Page: http://www.sparklingfloorservice.com
    Marine Hobbyist: http://www.melevsreef.com
     
    Marc Levenson, Nov 7, 2003
    #29
  10. http://www.premiumaquatics.com/Merc...PA&Product_Code=SP-LLC-S&Category_Code=Dosers

    That might be the perfect solution to what you want. It better be for $85 + shipping.

    Marc


    Pszemol wrote:

    > Assuming the most pessimistic scenario, the switch will fail 30 minutes after you
    > leave and you will have 30 gals of fresh water in your tank.
    >
    > Maybe the solution is to have to float valves/switches?
    > One for regular top-off, and the second and inch or so higher, for safety.
    >
    > It would greatly improve your chances of coming home and finding
    > everything in order... Both probabilities of switch failure will multiply giving even
    > smaller probability of overall failure - at least that is what I remember from school ;-)
    >


    --
    Personal Page: http://www.sparklingfloorservice.com/oanda/index.html
    Business Page: http://www.sparklingfloorservice.com
    Marine Hobbyist: http://www.melevsreef.com
     
    Marc Levenson, Nov 7, 2003
    #30
  11. Pszemol

    Raymond Guest

    Marc Levenson <melev@swbell.net> wrote in message news:<3FABB36E.358BB454@swbell.net>...
    > http://www.premiumaquatics.com/Merc...PA&Product_Code=SP-LLC-S&Category_Code=Dosers
    >
    > That might be the perfect solution to what you want. It better be for $85 + shipping.
    >
    > Marc


    The liquid level control is a great product from the RO membrane
    perspective but I'm not so sure it is all that great from a Reef tank
    perspective depending on how it is used. When the water level reaches
    the low water point the "switch" turns on and doesn't turn off until
    the water level has risen ~1 inch. If the water is being pumped into
    the tank/sump/whatever then the rise in water happens quickly and you
    would see a bounce in salinity. If it is hooked straight to your RO
    system and you have a pressure (bladder) tank then the water is still
    added quickly. The design is for connecting straight out of the RO
    filter without any storage tank so the water would be added at the
    rate the membrane can pass it. As long as that is the way it is being
    used then I would agree that this may indeed be the perfect solution.
     
    Raymond, Nov 8, 2003
    #31
  12. Pszemol

    Pszemol Guest

    "Raymond" <rdsmith@intcon.net> wrote in message news:e519c6f1.0311072217.25617919@posting.google.com...
    > The liquid level control is a great product from the RO membrane
    > perspective but I'm not so sure it is all that great from a Reef tank
    > perspective depending on how it is used. When the water level reaches
    > the low water point the "switch" turns on and doesn't turn off until
    > the water level has risen ~1 inch. If the water is being pumped into
    > the tank/sump/whatever then the rise in water happens quickly and you
    > would see a bounce in salinity. If it is hooked straight to your RO
    > system and you have a pressure (bladder) tank then the water is still
    > added quickly. The design is for connecting straight out of the RO
    > filter without any storage tank so the water would be added at the
    > rate the membrane can pass it. As long as that is the way it is being
    > used then I would agree that this may indeed be the perfect solution.


    My filter is giving 10gpd max when conditions are optimal.
    With my lower pressure and colder water is gives less...
    It should be ok :)
     
    Pszemol, Nov 10, 2003
    #32
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