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  • RO Water Filtration System

    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

  • #2
    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.

    Comment


    • #3
      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.

      Comment


      • #4
        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.

        Comment


        • #5
          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

          Comment


          • #6
            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; 30 November 2018, 03:11 PM.

            Comment


            • #7
              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. It’s 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).

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

              Comment


              • #8
                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; 30 November 2018, 07:39 PM. Reason: Commercial link removed

                Comment


                • #9
                  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.
                  I’ll 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.

                  Comment


                  • #10
                    Originally posted by sprezzatura View Post
                    I’ll 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, here’s the ROS 270 - I’m waiting for an in-line remineralisation filter.

                    Comment


                    • #11
                      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?

                      Comment


                      • #12
                        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?
                        It’s silly, isn’t it? My water is stripped to TDS 12 parts per million per litre. It’s too basic for stainless steel (corrosion) and flat for coffee. Great for drinking though. Ok through my Behmor Brazen.

                        Comment


                        • #13
                          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).

                          Comment


                          • #14
                            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, there’s a whole lot of stainless steel brew boilers that have been chewed up by chlorine, chlorides and low pH under pressure and above 85°C - 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.

                            Did your pharma plant RO operate under 7-12 bar of pressure? At 92° - 95°C? And how was your stainless? Some boilers lack enough chromium to resist rust and corrosion.

                            Comment


                            • #15
                              Originally posted by sprezzatura View Post
                              IIt’s too basic for stainless steel (corrosion)
                              And then:

                              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.

                              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.

                              Originally posted by sprezzatura View Post
                              Did your pharma plant RO operate under 7-12 bar of pressure? At 92° - 95°C? 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; 3 January 2019, 11:34 PM.

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