dfk41 I spoke to Mark in detail. The summary of the discussion is given below:

  1. The filter change sequence is descale —> sanitise —> filter change. The instructions are available online.
  2. The filter change is a function of water usage. The maintenance light will pop up after 2000L. In cases of low usage, the light won’t pop up; and, their recommendation is change in any case every 6 months.
  3. They don’t recommend using their unit if the CaCO3 is greater than 250. The 1 and 2 applies in this case.
  4. If the unit is used on locations where the hardness is > 250 CaCO3, the maintenance light or all lights will flash. This indicates a blockage in the filters. The sequence for this scenario is descale —> Sanitise —> Carbon Filter change —> Reset —> RO Filter —> Reset. The other filters are only need to be changed every 6 months. The users will also have to descale every 2-3 months in this case.

All instructions are available online.

Edit:

I hope I heard 2000L properly.

    @Rob1

    The description of the mineralisation filter on their website is as follows:

    Quick-Change Insertion Filters: Hygiene After-filter antibacterial calcium and magnesium bioceramics, adding a small 10-20 ppm of minerals.

    Not sure, it clarifies anything without the actual content!

    As I spoke to Mark from Osmio for another reason, I asked him this. He went quiet, did not confirm if these are from calcium carbonate or organic sources, paused and shared with me his experience at home.

    He feeds hard water and output from the mineralised RO is 54 mg/l of GH and KH respectively. He doesn’t think this can scale the espresso machine.

    It is all up in the air! 😊

    LMSC You can open the hot water from your machine - once a month or every 5-6 weeks, flush all the water out and replace it fresh Pure RO.

    I am expecting delivery of my Skuma next month, so reading this with interest.

    I have a Minima and really don’t want to feed it manually so I think doing this would need to be via the main tank. I suppose I could drain the service boiler, then fill the service boiler with the unmineralised RO water and then empty the water tank once the service boiler has filled and fill again with the mineralised RO water. Am I understanding this correctly?

        dutchy101 I suppose I could drain the service boiler, then fill the service boiler with the unmineralised RO water and then empty the water tank once the service boiler has filled and fill again with the mineralised RO water. Am I understanding this correctly?

        Yes! If there is an internal water tank in Skuma, you need to get that out to provide a pure RO to your minima.

        Usually, I don’t bother emptying the unused Pure RO from the espresso machine water tank.

        dutchy101 Skuma next month

        We are all looking forward to your detailed review mate! 😊

              LMSC Yes! If there is an internal water tank in Skuma, you need to get that out to provide a pure RO to your minima.

              There’s a function on the machine to dispense pure RO water (without the added minerals) by holding down the button for 2 seconds or so - presumably this will be fine to do?

              LMSC Usually, I don’t bother emptying the unused Pure RO from the espresso machine water tank.

              Music to my ears - if it tastes OK I suppose there’s no reason to.

              Thanks for the help!

                  JahLaza

                  Will scale in a service boiler at 125c quite quickly, probably less than a week if you steam for one flat white a day, but brew boiler is fine.

                  Consider just descaling the service boiler.

                  How much scale you can get is not possible to calculate as you don’t know what the added alkalinity is from….bioceramics could be silicates or phosphates. In any case, as the pure RO has alkalinity from carbonates, there will be at least some scale potential.

                      Rob1 Could he minimise the scaling of the service boiler by refreshing the water in the service boiler ie opening the water tap after steaming or am I missing the point?

                      • Rob1 replied to this.

                          Rob1 was really hoping the use of osmio would negate the need for any of that but I’ll do what I need to, to keep everything in order! I might just use ro or di water for a few weeks instead of any descaling (I think I might have access to some lab de ionised water) and that might clear things up?

                            coffeealex In this case it would be a very frequent and large amount of water to waste.

                            @JahLaza but then you’d be making coffee with that too…

                                I read these posts and there is a lot of info and some of it can to me at least seem confusing. There are mentions of KH and GH and alkalinity. I thought to ensure i keep my machine at the minimum level of scaling: i do the following

                                1. Buy a water hardness kit but not the strips

                                2. Start by measuring the hardness of my tap water as a CaCO3 figure with the kit

                                3. pour the tap water in to either a skuma or OZ ( leave out the jug versions for this)

                                4. extract the water from the RO machine with all filters installed ie mineral filter included

                                5. take another reading of the hardness and ensure it is no higher than 80 ( around the 40-80 mgl mark)

                                6. Pour that water into the water tank of the espresso machine

                                7. if using steaming periodically then flush some water from the hot tap so that the minerals in the service boiler are not accumulating.

                                8. Once every 3 months recycle the water in the service boiler with fresh RO water so that very few minerals are left

                                9. Alternatively use RO water with no minerals. But in this case add bicarbonate of soda to act as an anti corrosive property in the RO water.

                                10. If your machine has stainless steel boilers then there is no need to add bicarbonate of soda as no corrosion will take place but you may still want to add it to improve taste


                                  I have tried to simplify the procedure so that it keeps scaling to a minimum. Would the above work? or is it over simplified?

                                  Rob1 Have a look at the post I just made and help me please just to fill the dots .

                                    Rob1 but then you’d be making coffee with that too…

                                    I would just make espresso and top up with remineralised from the oz (I mostly drink Americanos),maybe it would make a difference,probably not for the 30 odd gms of said liquid?

                                    Unless the extraction changes?… apologies I really should take notes from the various discussions on this,I fully appreciate any help you can give as I know you’ve had to repeat yourself man many times before on this topic

                                    • Rob1 replied to this.

                                        JahLaza If you are just making americanos the water is ok and your 6 month refresh would be fine…probably. Probably better off just topping up from the osmio rather than using the service boiler just for energy efficiency.

                                        coffeealex take another reading of the hardness and ensure it is no higher than 80 ( around the 40-80 mgl mark)

                                        Not sure where you got that from. For the service boiler you’ll want hardness to be less than 40mg/l really if your alkalinity is 40mg/l too, but ideally, the hardness will be 0. While at 40KH you can have hardness up to 52GH at 125c, a very small increase in alkalinity will see the scaling potential increase quickly e.g 43KH at 125c and the threshold drops to 43GH…

                                        So for service boilers water hardness is ideally 0 with 40mg/l or more alkalinity, and for brewing espresso you’ll get good results too. Adding hardness in means flushing/monitoring a service boiler and/or descaling.

                                        coffeealex If your machine has stainless steel boilers then there is no need to add bicarbonate of soda as no corrosion will take place but you may still want to add it to improve taste

                                        Stainless steel isn’t quite as corrosion resistant as surgical steel and you have other things though like copper pipes and solenoids, a brass group etc. Not a great idea to be putting distilled or straight RO through a machine. I pour it directly into the service boiler, it’s not completely risk-free, but it doesn’t stay pure for very long.

                                        People who refresh the service boiler and use the remineralisation filter seem to be doing fine. If you want to just add bicarb you’ll probably be pleased with the results too. There’s no real need to complicate things.

                                                Rob1 Thank you for your replies. Clearly your level of understanding of water is comprehensive. It has made me realise that although I am trying to simplify everything some basic understanding of water chemistry is helpful.

                                                I am never going to have your level of Knowledge but the more I am reading the more the penny is dropping. So this is where I am now in my understanding:

                                                Using and maintaining an espresso machine and keeping reliability to a maximum requires good quality water suitable for the machine. This is based on the initial and unequivocal fact that the quality of water is probably the number 1 factor to minimise short/ long term machine problems.

                                                Starting from that baseline my understanding is that tap water is full of various minerals and that these will differ according to how the water is naturally filtered eg: there may be more chalky mineral salts dissolved into the water as it filters naturally which would make the water harder. Finally water authorities will add/ remove minerals to the water to purify it and/ or improve its perceived quality. The net result will be water that differs from area to area.

                                                From an espresso machine point of view removing these minerals through reverse osmosis or jug filters would at first seem the logical solution. i.e. if we remove calcium and magnesium minerals ( principal causes of limescale formation) then this would be job done? If only it were that simple.

                                                My understanding is that in so doing you are then affecting the PH level of water i.e. the acidity/alkalinity factor. Why does this matter? Well if you make water more acidic ( which is what happens when you remove all minerals) then corrosive factors come in to play. At first I thought Ok that only matters if you have brass boilers. Alas I also realise that although helpful having stainless steel boilers, a cursory look at most espresso machines will identify many brass pieces.

                                                That then brings the fact that adding something back is helpful. Hence where bicarbonate of Soda comes in as it raises PH and hence alkalinity values. There is also a taste factor for some who may feel demineralised water may not taste great eg zero water. Although I wonder if that is going to differ from person to person as surely if you remove all minerals from water then are you not effectively tasting the inside of your mouth?

                                                In conclusion for most a standard RO treatment with a few minerals put back in should do the job, along with some periodic refreshing of the service boiler along with an annual or half yearly check of the mushroom for signs of scaling. Ideally a simple wifi endoscope obtained at low cost from amazon inserted into each boiler would give a clear indication of how effective the quality of your water. something such as:

                                                endoscope

                                                Rob or anyone else am i starting to think along the correct lines or is my understanding still wide of the mark?

                                                    coffeealex you could always read Jim Schulman’s ‘insanely long water faq’ for more info!!

                                                    Edit: what I mean is the water thing is a deeper rabbit hole than this coffee thing!! See all the debates about it including the faq above mentioned. But I think you’re on the right track in your assessment above all the same

                                                        JahLaza you could always read Jim Schulman’s ‘insanely long water faq’ for more info!!

                                                        Thanks for that. For sure a cursory look gives some interesting pointers but also contains material that is more akin to doing a thesis than practical knowledge ie: B. Limescale Precipitation, pHs & the Langelier Index: pHs = 44.15 + log(S)/10 - 13.12*log(T + 273) - log(H) - log(A). ? BUMP

                                                        You are right if I went down the rabbit hole it would indeed be deep: I might struggle to find my way back out………… or it might challenge my sanity

                                                            coffeealex that’s why I was liking this thread here for a more ‘easy’ to understand for people, just want to hear what’s needed/risky in simple terms coz the detail can get so crazy with the water topic. And thanks to all who have advised here

                                                              For anyone interested in the use of an endoscope as mentioned in my previous post these were the camera results from in the past before and after descaling my izzo at a time that I was using only water from a jug with filter not Zero water I should add. Proof that getting the water quality right DOES matter!

                                                              coffeealex Well if you make water more acidic ( which is what happens when you remove all minerals) then corrosive factors come in to play.

                                                              Removing minerals will not make water more acidic; neutral pH is by definition the pH of pure water. The problem is that pure water will tend to absorb CO2 from the atmosphere, and that can turn it into a fairly acidic liquid. Buffering it with a weakly basic compound like bicarbonates (or weakly acid - but since coffee is acidic in nature very few people enjoy adding acid to it) keeps the pH close to neutral (within relatively large bounds). “Alkalinity” (as we use it in coffee making) doesn’t necessarily equate to a high pH.

                                                              If you remove calcium and magnesium compounds, or (bi)carbonate ions, scale won’t form. The problem is that Ca and Mg make coffee taste better to a large proportion of people, and bicarbonates are an easy method to raise alkalinity (which also makes coffee taste better, in addition to some anti-corrosion effect… which BTW isn’t always present, depending on temperatures and pressures).

                                                              It’s not necessarily complicated, but there are a lot of factors interplaying, and many are personal choices. In addition to the matter of “coffee taste”, there are significantly different opinions on what is a safe or acceptable amount of “corrosive” compounds (chlorides, sulphates, etc.), or a tolerable amount of/time to (de)scaling.

                                                                  CoyoteOldMan Thanks for clarifying that technical aspect re acidity. Is the fact that pure standing water is absorbing carbon dioxide the reason you often hear people say to only use water on demand as needed rather than leave large amounts in the espresso water tank? Also is there a simple formula to work out how much bicarbonate of soda to add if using pure water to bring the ph neutral or thereabouts? How do you measure very small amounts of bicarbonate of soda as I would assume you are talking about less than a gram a time?