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Thread: RO Water Filtration System

  1. #1
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    RO Water Filtration System

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello All,

    I thought it's about time I pulled my finger out and got serious with water.

    I'm looking to buy an RO Filtration System but not sure what system (or components) would be a good option. I plan to make water in batches. Filter 20L of water and then experiment with adding minerals. The unit will not be used to filter other water around the house, just the water I use for coffee and homebrew.

    The system will be connected to mains water.

    Location is Brisbane (Morningside) QLD.

    What does everyone recommend, and why?

    Thanks
    Ben
    Decent Espresso
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  2. #2
    Senior Member Lyrebird's Avatar
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    How often will you make the batches? A major problem with RO units is keeping the membrane sweet when the thing is not in use.

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    Quote Originally Posted by Lyrebird View Post
    How often will you make the batches? A major problem with RO units is keeping the membrane sweet when the thing is not in use.
    Likely around once per month, if needed I could make smaller batches so its once a fortnight. If needed I could connect to a kitchen tap.

  4. #4
    Senior Member Lyrebird's Avatar
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    OK in that situation I would do two things: firstly feed product water back through the system to flush it out before shutting down. Secondly run the system every two weeks or so whether you need the water or not: just use it to water your garden or whatever.

    FWIW I built my own RO system: mine was designed to do difficult separations so it's completely over the top for water but the same principles would apply. Get hold of a decent membrane unit (I used a GE Osmonics unit)* a high pressure pump such as a Procon vane pump and plumb it together with Swagelok fittings. Mine has a variable pressure regulating valve on the retentate outlet so I can adjust parameters on the fly, I think you could use a fixed one for water.



    *As above the unit I used was designed for adaptability for research purposes so the details aren't relevant here.

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    Quote Originally Posted by Lyrebird View Post
    OK in that situation I would do two things: firstly feed product water back through the system to flush it out before shutting down. Secondly run the system every two weeks or so whether you need the water or not: just use it to water your garden or whatever.

    FWIW I built my own RO system: mine was designed to do difficult separations so it's completely over the top for water but the same principles would apply. Get hold of a decent membrane unit (I used a GE Osmonics unit)* a high pressure pump such as a Procon vane pump and plumb it together with Swagelok fittings. Mine has a variable pressure regulating valve on the retentate outlet so I can adjust parameters on the fly, I think you could use a fixed one for water.



    *As above the unit I used was designed for adaptability for research purposes so the details aren't relevant here.
    Thanks Lyrebird,

    I'm quite interested in making my own system, I'll may even have a lot of the components around that I'll need (pumps etc).

    Ben
    Decent Espresso

  6. #6
    Senior Member Lyrebird's Avatar
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    I've had a look online for the housing I used but I can't find it, sorry.

    It's basically a stainless cylinder with a BSP side port and Victaulic couplings as the end plates. The end plates have the permeate and retentate ports in them. It's on loan at the moment otherwise I'd take a pic and send it to you.
    Last edited by Lyrebird; 30th November 2018 at 01:11 PM.

  7. #7
    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by bachamp View Post
    Hello All,

    I thought it's about time I pulled my finger out and got serious with water.

    I'm looking to buy an RO Filtration System but not sure what system (or components) would be a good option. I plan to make water in batches. Filter 20L of water and then experiment with adding minerals. The unit will not be used to filter other water around the house, just the water I use for coffee and homebrew.

    The system will be connected to mains water.

    Location is Brisbane (Morningside) QLD.

    What does everyone recommend, and why?

    Thanks
    Ben
    Decent Espresso
    Hi,

    I run a Puretec ROS2700 off mains water pressure. Itís a high-output dual Pentair membrane and I have added a needle valve downstream to adjust TDS from the remineralisation filter (calcium and magnesium). This system runs 2 Linea PBs and produces 2.0 litres per minute as tested at full mains (3bar).

    Iím buying a Puretec ROS270 (which produces 270ml per minute) for home use (drinking) and my coffee machine. They are simple and very affordable. Iíll probably post mix coffee water like you or install a remineralisation in-line filter.

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    Thanks Sprezzatura, looks like a nice unit.

    Does anyone have the Everpure LVRO-75HE RO System? It also looks like a nice and the filters seem to be more common.
    Last edited by Javaphile; 30th November 2018 at 05:39 PM. Reason: Commercial link removed
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  9. #9
    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by bachamp View Post
    Thanks Sprezzatura, looks like a nice unit.

    Does anyone have the Everpure LVRO-75HE RO System? It also looks like a nice and the filters seem to be more common.
    Iíll post an image when I install it. I also install and service 3M SGL2 reverse osmosis systems too. They are very good. Site Sponsor Coffee Parts has lots of Everpure systems - RO units; etc.

  10. #10
    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by sprezzatura View Post
    Iíll post an image when I install it. I also install and service 3M SGL2 reverse osmosis systems too. They are very good. Site Sponsor Coffee Parts has lots of Everpure systems - RO units; etc.


    So, hereís the ROS 270 - Iím waiting for an in-line remineralisation filter.

  11. #11
    Senior Member Lyrebird's Avatar
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    What's the point of a remineralisation filter?

    Are you not just undoing some of what the RO has just done, especially on a coffee system?

  12. #12
    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by Lyrebird View Post
    What's the point of a remineralisation filter?

    Are you not just undoing some of what the RO has just done, especially on a coffee system?
    Itís silly, isnít it? My water is stripped to TDS 12 parts per million per litre. Itís too basic for stainless steel (corrosion) and flat for coffee. Great for drinking though. Ok through my Behmor Brazen.

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    Senior Member Lyrebird's Avatar
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    Quote Originally Posted by sprezzatura View Post
    It’s too basic for stainless steel (corrosion)
    That makes no sense to me. Do you have a reference for that?

    To make things plain, I have worked in food and bev for over thirty years and have never seen stainless corrosion due to water being too pure.

    I once designed a water purification system for a pharma plant that got down to an equivalent TDS of ~0.03 ppm (close to the theoretical minimum* for water) and all the downstream piping was stainless. There were no corrosion problems.

    It's such a common furphy that some actual corrosion specialists put it to the test and found no evidence for it.


    * Pure water partly dissociates into hydrogen and hydroxyl ions, each at 10^-7 M, which is why neutral water has a pH of 7. Those ions add up to conductivity of 0.055 uS which is equivalent to a TDS of about 0.03 (depending on conversion factor).

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    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by Lyrebird View Post
    That makes no sense to me. Do you have a reference for that?

    To make things plain, I have worked in food and bev for over thirty years and have never seen stainless corrosion due to water being too pure.

    I once designed a water purification system for a pharma plant that got down to an equivalent TDS of ~0.03 ppm (close to the theoretical minimum* for water) and all the downstream piping was stainless. There were no corrosion problems.

    It's such a common furphy that some actual corrosion specialists put it to the test and found no evidence for it.


    * Pure water partly dissociates into hydrogen and hydroxyl ions, each at 10^-7 M, which is why neutral water has a pH of 7. Those ions add up to conductivity of 0.055 uS which is equivalent to a TDS of about 0.03 (depending on conversion factor).
    Well, thereís a whole lot of stainless steel brew boilers that have been chewed up by chlorine, chlorides and low pH under pressure and above 85įC - I know, Iím a La Marzocco technician. I know what works for this region and what doesnít.

    If water TDS is too low and boiler probe sensitivity isnít fine enough youíll have overfilled boilers. 12 ppm wonít cut it on certain commercial machines.

    Did your pharma plant RO operate under 7-12 bar of pressure? At 92į - 95įC? And how was your stainless? Some boilers lack enough chromium to resist rust and corrosion.
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  15. #15
    Senior Member Lyrebird's Avatar
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    Quote Originally Posted by sprezzatura View Post
    IIt’s too basic for stainless steel (corrosion)
    And then:

    Quote Originally Posted by sprezzatura View Post
    Well, there’s a whole lot of stainless steel brew boilers that have been chewed up by chlorine, chlorides and low pH
    I am confused what you mean by this, "basic" and low pH are opposites.

    Chloride corrosion of stainless is well understood I didn't think that's what we were discussing.

    Quote Originally Posted by sprezzatura View Post
    I know, I’m a La Marzocco technician. I know what works for this region and what doesn’t.

    If water TDS is too low and boiler probe sensitivity isn’t fine enough you’ll have overfilled boilers. 12 ppm won’t cut it on certain commercial machines.
    Sure, but again I didn't think that's we were discussing.

    Quote Originally Posted by sprezzatura View Post
    Did your pharma plant RO operate under 7-12 bar of pressure? At 92į - 95įC? And how was your stainless? Some boilers lack enough chromium to resist rust and corrosion.
    Not sure how this is relevant.
    Last edited by Lyrebird; 3rd January 2019 at 09:34 PM.

  16. #16
    Senior Member sprezzatura's Avatar
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    Quote Originally Posted by Lyrebird View Post
    And then:



    I am confused what you mean by this, "basic" and low pH are opposites.

    Chloride corrosion of stainless is well understood I didn't think that's what we were discussing.



    Sure, but again I didn't think that's we were discussing.



    Not sure how this is relevant.
    This is all relevant because Iíve posted an image of my RO which will have remineralisation and an adjustable needle valve to increase TDS and pH to to meet several espresso machine manufacturers minimum recommended TDS (90 ppm for LM; 50 ppm for Victoria Arduino - copper steam boiler can handle lower pH and TDS; and 75 ppm for KVDW) and will cost under $1000.00

    Your RO anecdote is interesting but this is Coffee Snobs - this is water for brewing coffee and for high-end prosumer espresso machines. We need RO around Brisbane. The average hardness is almost as high as Adelaide region and TDS is above 250 ppm.

    Ideal TDS - for my cup - is RO stripped and calcium/magnesium buffered to 100 ppm.
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    I'm in Brisbane too, Grange area. Currently looking into water filtration because thinking about buying an Izzo Alex Duetto and worried about corrosion.

    Would a Brita Purity C150 Finest filter do the trick instead of a big RO setup?

  18. #18
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    Quote Originally Posted by Lionaird View Post
    Would a Brita Purity C150 Finest filter do the trick instead of a big RO setup?
    Yes mate, that would be perfectly Ok...

    Just need to make sure you religiously replace the filter every 12 months to ensure adequate protection.
    I'm not up with the latest Izzo spec's but if they have s/steel boilers then I would suggest an additional carbon filter to be added in also, to ensure chlorine compounds are reduced as much as possible.

    Lyrebird may be able to chirp in with additional information in this regard...

    Mal.

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    Behmor Brazen - $249 - Free Freight
    Good idea regarding the carbon filter



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