water?

Discussion in 'Slipper Orchid Culture' started by bullsie, Feb 13, 2015.

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  1. Feb 13, 2015 #1

    bullsie

    bullsie

    bullsie

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    I would like to know if r/o water is the equivalent of distilled. It came up recently when talking of my r/o system. If there is a difference, what?
     
  2. Feb 13, 2015 #2

    gonewild

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    They are not the same.
    Distilled water has basically zero minerals because it is made by boiling water and condensing the steam. It also has zero buffering capacity for pH and can quickly become acidic once exposed to air.
    RO water has some minerals in it and is much better to use for watering plants.
    RO water should be cheaper is you have to buy it.
     
  3. Feb 13, 2015 #3

    Ray

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    The residual dissolved minerals in the RO water is dependent upon several factors, with the top four being:
    • TDS of the incoming water supply
    • What those minerals are
    • Age of the membrane
    • Design of the membrane.

    Basically, the membranes are designed to reject X% of the incoming dissolved solids. Most of those we see are in the 98%-99% range, although it varies from 93% up, depending upon the intended application. Even that is more than sufficient for orchids, though - If we use the excellent NYC water as a "benchmark" at 40-50 ppm, that "only 93%" membrane could match that with in incoming supply in the 600-700 ppm range!
     
  4. Feb 13, 2015 #4

    NYEric

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    Basically they are "equivalent".
     
  5. Feb 13, 2015 #5

    naoki

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    Is distilled water easily available?

    In biology lab (we do DNA and some RNA works), we usually don't use distilled water. We call it ddH2O (double distilled), but in reality, it is deionized water (we use Mili-Q for lab works). Here is some info about different methods of water purification:
    http://en.wikipedia.org/wiki/Purified_water

    In practice (for growing plants), RO should work as others said.
     
  6. Feb 14, 2015 #6

    NYEric

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    yes, they sell it in gallon jugs at Walmart.
     
  7. Feb 14, 2015 #7

    naoki

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    Oh, OK. Thanks, Eric, I didn't know it. I wonder if it is really distilled.
     
  8. Feb 14, 2015 #8

    Ray

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    I have some customers that raise dendrobates (poison dart frogs), and a few others with marine tanks, and they are all very keen on very pure water, and they simply attach a DI column after the RO. That is probably as close as anyone will come to distilled.
     
  9. Feb 14, 2015 #9

    bullsie

    bullsie

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    Ray, what does the DI column do on an r/o system?
     
  10. Feb 14, 2015 #10

    naoki

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    Usually deionization (DI) column contains ion exchange resin to removed charged ions. It's an additional step to remove more ions.

    Is the operating cost of DI expensive?
     
  11. Feb 14, 2015 #11

    Ray

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    The DI column is added to remove the last few ppms the RO system doesn't.

    The ones I carry are $35, and are good for about 1000 gallons if the incoming stream is 10 ppm, 2000 if it's 5, etc.

    From a plant perspective, I think it's a waste of money.
     
  12. Feb 16, 2015 #12

    naoki

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    Thanks for the info, Ray. It isn't as expensive as I imagined, but I agree that there is no point for orchids.
     

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