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  • RO water

    Hi there,

    Does anybody know what problems are associated with ro water being to soft <120 PPM or 8 degrees german. There is lots of info about too hard a water but the only info i could find was very scarse. And if possible why?

    Cheers Paul

  • #2
    Re: RO water

    Paul,

    I'll share what I know with you.

    We were taught in trade school to use RO water for mixing with your fountain solution, however they never really mentioned hardening the soft water. It wasn't until many years later that I discovered from a Chemist that you need to harden RO water to make it more suitable for mixing with Fountain Concetrate.

    The ideal 'hardness' is 12 German Hardness meters. (I think meters is the term).

    So we used a caclium-based hardener and sent off samples to the chemist who confirmed that we had indeed reached 12 German hardness. Concetration of about 0.5%.

    We then ran with the hardener for about 3 months and found that we got a lot of calcium build-up on the rollers and that ink would be stripping on the rollers in those areas. Tried all kinds of calcium-cleansers with little or no affect. Needed to remove rollers to clean them by hand. (off topic: I've heard recently that B├│ttcher make the best calcium-cleaning-paste. It works quickly!)

    So we stopped using the hardener since it was causing more problems than it solved. We found that going to RO alone made a dramatic difference in the quality of our printing. (old press too)

    So for years we've been running without a hardener, until recently we spoke to a new chemist who asked us whether we're using a hardener. I explained the storey and he said, "Yeah that stuff was pretty bad. But water hardening has come a long way since then and we don't use calcium anymore".

    Now I tried it and also changed to their fountain solution brand at the same time, so I can't guarantee which was doing most of the good! But it was a noticeable improvement.

    In summary: Hardening RO water is good, but stay away from the Calcium-based products!

    It's all I know about the topic.

    Comment


    • #3
      Re: RO water

      Hi Dwane,

      Thankyou for your reply, my experience is exactley the same as yours. Once the Ro gets to 150PPM or 300Ms then i get calcium deposits after a days printing. When i go down to 80PPM or 160Ms then damping seems the same but without the calcium build up. We now de calcify once a week, i tried a few products but i apply them over the ink before a washup instead of after. It seems to give the calcium a better ride out of the ink train, then a quick spray of warm water after and all seems ok.

      Do you struggle to achieve low ph with the water softer, i did a controlled mix with our softer water and the Ph was aprox 0.2 higher than with 300Ms water?

      Cheers Paul

      Comment


      • #4
        Re: RO water

        Paul,

        When you are talking about RO, do you mean before you add fountain concetrate?

        Are you talking about conductivity when you're referring to 300Ms? The Microsemens?

        If you are talking about RO before you add fountain concentrate and Conductivity readings we are no where near 300Ms. Our 'water-guy' came in a few days to replace the membranes on our RO system and drinking fountains etc. And he told me that he took a reading of about 4Ms at the third or fourth filter and he expected the first 1st filter to have more than that.

        But that means we were only around 4Ms max at our worst point.

        But we may be comparing apples-to-oranges here.

        Also, I find that my pH meter is really inconsistent and depending on how long I put the meter in there for, I can get anywhere between 0.2-1 variance! So I don't really use it. (well I don't trust it)

        We never have to do de-calcifying. I suppose the stocks we're using don't contain much calcium. Are your stocks also a source of calcium do you think? Sounds like a pain to have to always apply de-calcifying products.

        regards,

        Dwane.

        Comment


        • #5
          Re: RO water

          Hello Dwane,

          When i use the term RO i mean before any concentrate has been added other than the water hardener. Pre filtration our water varies from 300-500 Microseimens Ms, after filtration but befrore rehardener we get down to about 40 Ms after a filter change. With re hardener at 0.6% i get to 150 Micro seimens. I think were using different terms for measuring conductivity im using micro seimens, i think there is a milli seimens as well.

          Paul

          Comment


          • #6
            Re: RO water

            Paul,

            OK, I understand now.

            You were talking about the reading after adding hardener. You see I've never measured that before. We usually add the hardener with the fountain solution and then fill up with RO.

            That's pretty amazing that you still get 40 Micro seimens after a filter change. We get nothing. However we've got a 4-stage filter system which is pretty slow (although 2-3 times quicker than our previous 4 stage filter system).

            Are you perhaps running a 2stage or 3 stage system to get more water in less time? (I'm sure it's working for you)

            Dwane.

            Comment


            • #7
              Re: RO water

              Hey Dwane,


              good to hear from you again, we run a 4 filter system one pre filter which is made up of a woven twine, and three big filters. the pre filtration is cool, giving consistant results but the doser which adds the re-hardner plays up some time giving 75PPMto 120PPM. Found a few issues with the alcolour spring on the link roller today which may cause issues if this cures my problems i wil start an new post notifying people..

              Happy printing

              Paul

              Comment


              • #8
                Re: RO water

                Paul,

                How old is the press? Or specifically how long since the last failure of the spring?

                The reason I ask, is perhaps it's something that could be replaced before it becomes a problem next time. Of course there are many variables to consider and it could have been operator caused. But if it's a recurring thing a preventive maintenance application could remind you to replace it before it fails.

                I'm not sure whether you've seen my recent post [Free Maintenance Scheduling Program|http://printplanet.com/discuss/threa...threadID=1764] but I found this free application that can schedule maintenance from last completed date or ....drum roll..... meter readings.....which could be used as impressions.

                So if you're part fails every 2.5 million impressions, replace at 2 million and perhaps avoid unscheduled maintenance.

                Idealistic?

                Absolutely.

                Waste of time?

                Perhaps.

                Food for thought?

                Defintely!

                Comment


                • #9
                  Re: RO water

                  Hi Dwane,

                  The spring mechanism i speek about hasnt broke, it has a shaft running through the spring with the shoulders to hold the link roller in position, there is a mounting point at its joint with the damping form roller journals and a point on the side frame, this spring has a thread on the one end and you can alter the pretention on the spring, i think this is more by nessecity than design. But the link roller was heavy to the first form and not touching the damping form untill i applied more preasssure. But after a bit of a fiddle and a days production is has made no difference. As for the maintanance software its a good idear but our managers dont understand pro activity there too busy looking a u tube or google to want to try this.

                  Paul

                  Comment


                  • #10
                    Re: RO water

                    Paul,

                    - But after a bit of a fiddle and a days production is has made no difference.

                    Sorry to hear that.

                    - As for the maintanance software its a good idear but our managers dont understand pro activity there too busy looking a u tube or google to want to try this.

                    Yeah, it's an ever present temptation these days....

                    Comment


                    • #11
                      This is really confusing me... I see hardening agents sold, like CALCIT from bottcher, and SALINOFIX from hostmann, so i feel like i need to reharden my RO water... but i ask my school instructor and he says no need... he says he never heard of it .... water coming out of our RO is 40Ms(micro siemens).
                      is the conductivity that is added by the fountain enough to eliminate corrosion and provide dampening good for printing?

                      Comment


                      • #12
                        Water chemistry basics

                        I found this english text on website Mongabay.com, devoted for aquarists, but informations are equally valid for basic understanding.

                        PH
                        The pH scale is a scale which is used to measure the acidity or alkalinity of a substance. The scale ranges from 0-14, with 0 being the most acidic, and 14 being the most alkaline. Water with a neutral pH of 7.0 has an equal ratio of H+ ions to OH- ions. Water with a pH below 7.0, is considered acidic (having a more H+ ions than OH- ions), while water with a pH above 7.0 is considered alkaline or basic (having a more OH- ions than H+ ions). Almost all freshwater fish inhabit waters with a pH from 5.0-9.0, with the majority of these inhabiting water with a slightly acidic to neutral pH (6-7.5).

                        Lowering the pH: The pH can be lowered by using a pH-lowering chemical. Be aware that many pH-lowering products use phosphate-based chemicals. Phosphate is a nutrient that encourages algae growth. In hard water, the pH may be difficult to lower. First, soften the water by peat filtration or reverse osmosis, and then try lowering the pH.

                        Water Hardness

                        The degree of water hardness relates to the amount of dissolved minerals, especially calcium and magnesium, in the water. Water hardness is generally expressed in the amount of calcium carbonate (CaCO3). Water hardness is measured in ppm (part per million), kH (carbonate hardness), and dH (degrees of hardness) or gH (general hardness). Water is expressed as soft (having few dissolved minerals) or "hard" (having many dissolved minerals. General levels of water hardness are expressed in the table below (1 dH is equivalent to about 17 ppm).

                        very soft 0 to 70 ppm 0 to 4 GH (dH)
                        soft 70 to 135 ppm 4 to 8 GH (dH)
                        medium hard 135 to 200 ppm 8 to 12 GH(dH)
                        hard 200 to 350 ppm 12 to 20 GH (dH)
                        very hard over 350 ppm over 20 GH (dH)

                        For most aquariasts water hardness is not particularly important. However, excessively soft water can cause problems. Because softer water has less buffering capacity due to a lack of CaCO3 (a natural buffer), and is subject to pH crashes, where the pH falls dramatically causing harm to aquarium inhabitants.

                        Carbonate Hardness: Carbonate hardness (kH) is not used as a measurement of hardness as often. KH includes the presence of minerals and charged ions, other than Ca and Mg, dissolved in water.
                        Changing the Water Hardness: Water hardness can be manipulated in several ways. To make the water softer, the water can be filtered through peat moss or filtered through a reverse osmosis system. Ion exchange resins also can be used to lower the water hardness. Boiling water for a period of time can also reduce its hardness. To harden the water, filter the water through dolomite or crushed coral until the desired hardness is reached.

                        Electrical Conductivity: By running an electrical current through the water, the level of conductivity can be found. Conductivity indicates the amount of ions (electrically charged particles) are in the water. The higher the water hardness, the greater the conductivity. Testing the conductivity of the water only finds the total amount of ions present in the water, and does not give the origin of the ions, whether they are Mg, Ca, or Fe.

                        Any comments?

                        Comment


                        • #13
                          this is very useful indeed... it makes me feel that PH would crash... BUT with the current fountain solution buffers don't u think PH is stable enough? also doesn't the conductivity added by the fountain solution make up for the soft water? doesn't it make it harder?

                          Comment


                          • #14
                            Straight, properly filtered RO H2O is the best in my opinion, without further treatment. There are other treated waters of course but straight RO water will give you the best chemistry; no matter what etch, subs or added IPA you may be dosing.

                            Comment


                            • #15
                              D Ink Man, can you explain your experience? why shouldn't i reharden the RO water, isn't it corrosive? or does the fountain added make it not corrosive?

                              Comment

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