Making water for coffee – SodaStream Method (Best recipe so far!)


It appears that there were some issues downloading the old spreadsheet do I’m attaching it here as a direct download in xlsx format.


In my previous guides I looked at making water that was good for making coffee as I live in a soft water area and with bottled water not being ideal. Although a big improvement I was getting inconsistent results and sometimes things were unbalanced for no obvious reason. So after an interesting conversation with Gary Dyke about the possibility of collecting rain water and using it for coffee, whilst sat stationary on the M6, I got to thinking about natural water sources over bottled water sources and started reading up.

I found some interesting articles on ground water and how hardness forms in nature. Most hardness comes from dissolved Calcium Carbonate in the ground water as opposed to Calcium/Magnesium Sulphate or Chloride, these can still be present but in a lot of cases in very low concentrations. I started to wonder if there was a difference between the types of hardness that these chemical created. After some more research, mainly on beer brewing forums, I found that the answer seemed to be yes.

You have permanent and temporary hardness.

Permanent hardness is Ca/Mg ions that are associated with Chlorides and Sulphates, these generally don’t come out of solution when you boil water.

Temporary hardness refers to Ca/Mg ions that are directly associated with carbonates and bicarbonate, these generally do come out of solution when you boil and result in scale.

There is a lot more info on water in the beer brewing circles and they differentiate between these hardness types when talking about beer brewing water. Bringing this back to coffee, generally speaking, the best coffees that I have tasted have been made from water with naturally occurring carbonate hardness (temporary hardness) and generally with twice the level of hardness to alkalinity, this is the case with water from the Has Bean roastery which is held in high regards and produces very balanced coffee with great body. This again comes back to the same ratios that we looked to achieve in the previous articles however now we are differentiating between permanent and temporary hardness which we weren’t back then.

I had tried previously to dissolve Calcium Carbonate in water however it is almost insoluble (about 20mg/L at room temp) so I needed another way to try and get this off the ground. During my research I had learned that naturally occurring carbonate hardness comes from water underground. Higher pressures at the lower depths result in more Carbon Dioxide (CO2) dissolving into the water, this then lowers the pH due to the formation of carbonic acid. Since calcium carbonate is so abundant in the ground and also soluble in weak acids you now end up with water that can dissolve a reasonable amount creating carbonate hardness.

With this all in mind I mulled over how I might emulate this at home so I set to work on a test.

So what’s the answer?

In the end it was quite simple, I came up with the idea of using a SodaStream to take RO water, inject it with CO2 under pressure to create carbonic acid, I would then add calcium carbonate which would now dissolve and I would then dilute this back down to the desired hardness level.

The good news is that it worked and after a bit of messing I was easily creating water that resulted in the most fantastically balanced coffee with great mouthfeel clarity and taste. For me the new water was in a league well above the previous method but I wanted to make sure so I took some round to Gary for taste testing. Gary confirmed that the water was as good as I had thought so I started to look and refine the process and tweak it to be as perfect as possible.

Between Gary and myself we ended up preferring hardness levels of around 110-120 mg/L. As these hardness levels result in a TDS of around 70-80 mg/L and the ideal is 100-150 mg/L I decided look at an addition to increase this and also to add some Sodium Chloride into the equation at around the 10 mg/L recommended value as given by the SCAA. I chose to make the addition with natural Sea Salt which contains about 70% NaCl but also potassium and other minerals that occur in ground water. This was the icing on the cake. The water ends up at about 120 mg/L TDS, 120 mg/L Carbonate Hardness and 60 mg/L alkalinity (2:1 ratio naturally occurs when Calcium Carbonate dissolves in the acidic water).

The final step in the process was to filter the water to remove and particular matter. I decided to go with a 5L Britta filter and BWT Mg+ filter cartridges. These cartridges filter the water and also exchange some of calcium ions with magnesium which, according to Maxwell from Colonna and Smalls, should increase sweetness again and also reduce scaling slightly, win win!

So why bother I hear you ask? Well, having water of this spec means that you get extremely consistent and tasty brews. The resulting body and mouthfeel is optimised. The acidity and bass notes are balanced and increased sweetness is there as well (The NaCl seems to increase the perception of sweetness). The water is pretty stable to it won’t attack your espresso machine.

Are there any downsides? Yup, it’s a bit of a faff and at my preferred hardness levels you are going to get a small amount of scale in your espresso machine, however I believe that it’s worth it if you are using either bottled water or you live in a very soft water area. If you have naturally good water then I would recommend that you simply filter that as it will be lot easier and should result in a similar profile.

So what equipment do you need?

Pure Calcium Carbonate Powder (can be purchased from ebay) you use about 1-2g per 10L of brew water.
Posh Sea Salt (26g dissolved in 1L RO water)
A Soda Stream (I got mine from Argos for about £30)
RO/Distilled water – can buy from most aquatics centres – you will need a lot of this as it makes up the bulk of the brew water, 10p per L
TDS meter – from ebay/amazon for about £14
My spreadsheet to perform a couple of calculations during the process (Can be viewed online here or downloaded directly here)
A graduated 10ml pipette
A Britta filter and some BWT Mg+ filter cartridges
Finally, a pack of Sharpies or similar for marking up the bottles

What do I do with all this stuff?

1 IMG_20150716_180622

Fill your Soda Stream bottle with RO water to the line. Lock it into the SS and blast it until safety valve pops (as per SS instructions)

3 IMG_20150716_180717

Weigh 1.5g of Calcium Carbonate and add it to the fizzy RO water. Put lid on bottle quickly. Shake a few times.

Leave the resulting solution overnight in the sealed bottle so that the solids fall to the bottom of the bottle (this is important or you will end up with loads of sediment in your water which you don’t want and you may also increase the hardness after you have measured it)

Open the bottle and tip a small amount of water out of the bottle into a little cup.

Measure the TDS of the water, after leaving it to sit for a few mins to let the bubbles dissipate, I get the best reading from taking the TDS meter in and out of the water a few times. The reading will change but I go with the figure that comes up most often.

Once you have this TDS reading you then stick that into my spreadsheet and enter your desired brew water hardness. The spreadsheet will tell you how much of this Calcium water you need to add to how much RO water to make the desired hardness. It’s usually about 300-500ml Calcium water to make a 5L batch of brew water.

6 IMG_20150716_183940

Once mixed well you then add 1ml of Sea Salt solution for every litre of brew water and stir again.

I then take this and filter it through a BWT Mg+ cartridge in a Britta 5L filter.

That’s it!

61 Comments. Leave new

  • Great work, Spencer, thanks for sharing! Looks like you finally nailed it. 😉

    Brilliant idea with using a sodastream to get CaCO3 in solution. I have one question to that, though, have you tried also checking the TDS reading after carbonation, but before adding the CaCO3? Since the CO2 is converted to carbonic acid, wouldn’t the TDS change just from that process? And could it be that some of the carbonic acid immediately changed to hydrogen carbonate ions?

    And a second question: Do you know if the Brita filter is only exchanging calcium ions with magnesium, or is it also doing/adding other stuff?

    Thanks again, this is really awesome!

    • Thanks SZA, I’m very happy with the results I’m getting!

      I’ve have not measured TDS directly after carbonation and it’s possible that it does result in a TDS increase however, I don’t believe that this affects my method in any way as I measure the final TDS, Hardness and Alkalinity. I then take this information to create the conversion factors and ratios that I use to estimate the final water specs, so I am not relying on TDS at that stage. The results are very consistent and reasonably accurate so it still wouldn’t change anything I did even if it did affect TDS.

      I’m not using a Brita filter media, it’s a Brita filter but a BWT cartridge and this is responsible for the ion exchange. I’ve not noticed it doing anything else to the water however it couldn’t rule it out.

  • Yep, this water is superb – nothing off the supermarket shelf comes close.

    Everything you need for amazing tasting coffee but without the problematic build-up of scale attributed to other ground waters I have used .

    Good work!

  • Excellent work Spencer. Hats off to you for the amount of work you’ve put into this and for documenting it all.

    Thanks for letting me have a sample of this. I’ve tried this water over the weekend and I’m pretty stunned with the results.

    Using it produces a significant improvement in the cup. Flavours are more pronounced, distinct and livelier.

    Having used it with both espresso and brewed it’s produced some fantastic results so far. It’s a bit like changing the channel to the HD version of the same program.

  • Chris Schaefer
    September 8, 2015 6:59 pm

    Fantastic work! And a great use of the Soda Stream!

  • I’ve always fancied picking up a Soda Stream to help conjure up memories of days gone by…
    You’ve now given me the perfect excuse.. along with a project that will supply me with perfect water for my coffee..
    Perfect!! Thanks you 🙂

  • And when sorting out the kitchen cupboard last month I threw my soda stream away .
    Great new look to your blog and as always a good interesting and informative read.

  • Thanks Spencer! Quick question – what’s the TDS range for the final product?

    • Hey Wyatt, using the recipes here I get somewhere around 10-120ppm. I prefer slightly higher than lower but you have to beware of scale. I’m just working on a new recipe that mixes the previous two method and initial tests are good 🙂

      • Looking forward to hearing about the new recipe! I’ve made a couple batches using this water, and the TDS of the final brew water is usually right around 90 ppm. I’m wondering if this is due to error in measuring the Calcium water TDS. The reading on my TDS meter swings up to 100ppm on any given day, and never really becomes stable.

        Couple other quick questions – is it 1ml of the salt water per L, or 10 ml? And we’re weighing everything, not measuring the volume, correct?

        Thanks again for the work you’re doing here! Its fantastic not having to buy bottled water anymore!

        • Yeah measuring the TDS is problematic as bubbles form on the probes which makes it variable. I usually take a few readings and select the most common 🙂 I think you might be right about 90-100ppm I think I started adding more as it tasted nicer 🙂

          Salt water should be 0.8-1ml per L and I weight everything as it’s more consistent than volume. The only volume based measurement is the salt water and I have a pretty decent pipette for that.

  • Thanks for the details Spencer! I’ll try increasing the calcium water addition and see what happens as TDS increases.

  • Hey Spencer!

    Thanks for all the hard work here. Do you think the amount of CO2 you inject into the water is crucial?

    The reason I ask, I have a glut of C02 fire extinguishers that I use for injecting Co2 into my fish tanks. I also have a spare regulator. So I can easily stick a tube into a bottle of water and fill it with CO2. Is the pressure aspect important?


    • Honest answer is that I have no idea. Like everything in coffee it’s about repeatability. Using the sodastream’s overpressure mechanism is an easy way for me to achieve consistent dosing of CO2, whether it’s the best amount is something that I can’t answer 🙂

  • Great work, excited to try it out!
    I am not doing any espresso, just brewed coffee like V60, aeropress, etc..

    2 questions here:
    (1) Why not use MgC03 in the same stage as CaC03, and set it at a 1:0.5 ratio?
    (2) Can the final stage of filtering the water be eliminated? What would i lose?

    • Hi Bruce, sorry for the delayed response. In answer to your questions

      1. Yes you can, I’ve done some testing with this and results are positive however this requires maintaining 2 solutions etc…
      2. I prefer filtering as you end up with some CaCO3 suspended in the water even after it settles, whilst this is not so bad for brewed only I prefer the filtered option. Again it’s down to personal preference.


  • Really cool stuff!!! Can you use magnesium carbonate, in place of calcium carbonate for avoiding the Brita BWT step?

  • Okay– see the answer to my question above…… apologies!

  • Great article Spencer. I would like to try making my own water but the SodaStream is quite expensive at the moment (around £60-70). Soda syphons are a cheaper alternative but I’m not sure how much CO2 to inject. I’ve managed to find some info on the dosing of the SodaStream – the 60L cartridgemakes 60L of soda but I can’t find anything on the actual size of the bottle in order to convert to the soda syphon gas cartridges. Is the volume written somewhere on the cartridge?

    • Spencer Webb
      March 23, 2016 1:06 pm


      the volume isn’t on there but it does say that it holds 425g of CO2. Maybe test your method and see what the TDS of the resulting water is once you have added the CaCO3 and left it over night.


  • Thanks! That should make about 7g of CO2 per liter of water. I’ve just started reading on the topic it’s still hard for me to get my head around it.

  • Have you seen this thread: where @ rpavlis says:
    The thing one really wants in water other than water is bicarbonate ion to keep it a bit alkaline. There are massive concentrations of potassium in coffee beans, about 50% of coffee ash, about 2% of the dry weight of coffee beans! Thus one can add potassium bicarbonate to water and thus not add alien things to the mix. The potassium in added potassium bicarbonate is truly negligible relative to the huge concentration of potassium in the beans.

    `Potassium bicarbonate is directly soluble in water so sounds like an easy preparation. What do you think?

    • Spencer Webb
      April 4, 2016 2:44 pm

      I’ve not seen this thread particularly but everything I add into my water has a purpose and I don’t really have any need to add alkalinity without adding hardness as keeping alkalinity down is usually the biggest problem.

  • Spencer, this is fantastic work and the Soda Stream idea is brilliant. Thank you.

  • Hey Spencer, I’ve been following your water recipe and the quality of my coffee has dramatically improved. One observation I’ve made however is the difference in TDS before and after passing through the BWT filter. I’m noticing an approximate drop of about 40 TDS, which I guess is to be expected as the filter is catching some of the suspended solids. You say that 120 TDS is your preferred hardness, but is this pre or post filtering?

    • Hey Stuart thanks for the feedback. I can’t remember if I’m being honest. I don’t perform the final filtration these days. I’ve a vague recollection the best water was 120tds post filter.

      Have a go with both and see what you think!

      • Thanks Spencer, I tried both and definitely prefer around 120 TDS post filtering.

        What made you stop the final filtration stage? Are you doing anything different nowa days to get some Magnesium in instead of the BWT cartridge?

        • Laziness, that and the fact that I actually prefer Calcium to Magnesium in my water. I do add a small amount of Mg back in afterwards but only a very small amount.

          • Dear spencer, thanks for sharing this recipe! The water is great, but I Guess I was hoping to push it further! And following the thoughts of stuart, I find that I like the water at 120ppm and above post filter. Just that the calculation is abit off on the excel, so I’ve just started adding more of the CaCO3 addition to get the result!

            I’m just wondering if you’ve not filtering through the Bwt mg2+ , how did you make the Mg addition and any ratio you could advise? As I liked the calcium but it had been replaced when putting through the filter.

            I have some MGCL2.6H2O (food/lab grade) Mineral. Would that be any good? Read your previous post that chloride actually makes the water sweeter?

            Would love to hear your thoughts! 🙂

          • Spencer Webb
            August 2, 2017 7:45 am

            So my method and calculations are not exact, they were created via experimentation and as such are guidelines that will get you in the ballpark, tweaking is always required to get the best out of it 🙂

            Local factors such as pressure, temperature, water pH, how much CO2 your soda stream adds to the water will all effect the outcome.

            When adding Mg separately (i.e. not with the Mg2+ filter) I used either MgCL2 or MgSO4. I experimented and preferred a 50/50 mix of CL2 to SO4 by concentration of ion. That seemed to give the most balanced taste profile. I usually restricted the Mg as well as it starts bringing in off flavours IMHO.

          • As I’m not chemistry trained, and can’t figure this out. Just to add on what I know is the Molar mass of MgCl2·6H2O is 203.3027 g/mol.

            Could you advise how shld I make the addition of the MgCl2·6H2O. And how will it impact the ppm of the water?

            Cheer! And many thanks!!

          • Thanks spencer for your reply.

            Just wondering if you could share with me the recipe or how do you make the 50/50 Cl and S04 addition? And usually how much do you add?

            I had made an addition of the mgcl2. And tested by adding a few grams and measure the ppm. Just that I feel the water isn’t as balanced as compare to the ones I’m putting through the filters.

            Any thoughts? Really appreciated your sharing! 🙂

            Would love to give it a try and see how it goes. With that say, after much trial and errors, I’m getting way better water than before!

  • Hi Spencer,

    I’ve been reading your posts, as I’m very much interested in maximizing coffee flavour potential through water chemistry. I’m wondering about the step where you filter your calcium infused water through the BWT Mg2+ cartridges, since apparently they work to remove calcium from the water (according to BWT themselves). I’m sure you already know this, and there’s probably a maximum amount of calcium that can be removed (or something similar), but I was just curious since that aspect of the Mg2+ filtering had me a bit confused.

    Thanks for your work, and looking forward to your thoughts on this.


    • Hi Matt,

      those cartridges swap calcium ions for magnesium ions. As you suggested they don’t swap all of them at these concentrations so you end up with a mix of Ca and Mg ions which is preferred by many. That filter stage also served two other purposes, they removed any left of particulates left over from the Calcium Carbonate step and they also remove undesirable flavour compounds if they exist.

      The step is optional, you can choose to not filter and keep the calcium or use Magnesium Carbonate if that works for you.

      Try for yourself and see which you prefer 🙂

      • Thanks very much! I’m about to make my first Sodastream solution. I might experiment with magnesium chloride as opposed to carbonate, since you suggest that the chlorides increase sweetness. I will let you know how it goes. Cheers!

        • Hi Matt,

          good to hear! FYI you do not need to use the soda stream method with Chlorides as they dissolve readily in RO water. The Soda Stream is only required to make Calcium Carbonate solution as this is essentially insoluble in water. Best off looking at my other methods if you want to go down the Chloride route 🙂

          • Hi Spencer,

            I’ve been experimenting with this method, and also trying to wrap my head around some of the chemistry involved (which has included some of Chris Hendon’s and Maxwell Colonna-Dashwood’s work). I am not a chemist, so I might be way off with my assumptions/calculations, but one particular revelation has me curious, and has prompted this reply; it seems to me that what results from dissolving Calcium Carbonate into a Carbonic acid solution is actually Calcium Bicarbonate ( In their “Corrigendum” to “Water for Coffee”, Hendon and Colonna-Dashwood suggest that (I’m assuming a pure solution here) Ca(HCO3)2 contains 122g/mol of HCO3-. Given that the molar mass of Calcium is around 40 g/mol, this would seem to indicate that the total molar mass of Calcium Bicarbonate (~162 g/mol) is made up of the 122 + 40 (HCO3- + Ca++). One thing I’m confused about is that, according to the Wikipedia entry on Ca(HCO3)2, there should be both bicarbonate AND carbonate ions. But Hendon and Colonna-Dashwood are apparently saying it’s only Calcium and Bicarbonate. Anyway, as I mentioned I’m not a chemist, so all of this might seem ludicrous. The reason I’m bringing it up though is that I’m trying to understand how the sodastream method is letting you achieve the proper levels of GH and KH (in ppm as CaCO3).

            I’ve attempted to make some calculations myself, and they assume what the corrigendum says (e.g. 122 g/mol HCO3- and 40 g/mol Ca++). Here goes…

            These figures yield a 3:1 ratio of HCO3- to Ca++ (HCO3- as HCO3- and Ca++ as Ca++)

            But, when converted to CaCO3 equivalents, (dividing by 1.22 for HCO3- to get HCO3- as CaCO3 — multiplying by 2.5 for Ca++ to get Ca++ as CaCO3), a pure solution of Ca(HCO3)2 yields almost identical amounts of HCO3- as CaCO3 and Ca++ as CaCO3 (49.6% and 50.4%, respectively), according to my calculations.

            I tried to make some brew water this morning, attempting to hit the SCAA recommendations (40 mg/L of HCO3- as CaCO3 — 68 mg/L Calcium hardness (made up of Ca++ and Mg++ as CaCO3)) but I wasn’t happy with the results. The coffee ended up sharply sour and empty, which seemed to indicate that both my GH and KH were lower than they should be.

            Anyway, I have some more questions, but they’re related, so I will leave it there for now, in the hopes that you can shine some light on this conundrum (which might answer the other questions I have as a result).


  • Ahh… I see the error of my ways. I was mistakenly using the percentages of molecular mass to determine concentrations (e.g. calcium vs bicarbonate) but I was then using a TDS meter, which is measuring cations and anions. So Ca(HCO3)2, as far as a TDS meter is concerned, doesn’t split into 75% bicarb and 25% calcium, but rather into one calcium cation and two bicarbonate anions (which is what you were referring to with the 2:1 split in your post).

  • Hi Spencer, thank you so much for all the brilliant information. I have been reading all your water posts several times already.

    I do have a couple of questions though: If not performing the final filtration, how much MgSO4 would you then add? Say in grams to a liter? Or with your solution from post #2?

    Also, how important is it that the calcium carbonate is food grade? The stuff I have found is ‘industrial grade’.

    Again thanks!

    • Spencer Webb
      August 2, 2017 6:58 pm

      Hi there,

      presuming that you are using MgSO4*7H2O, then I would start around 0.1g per L and experiment from there.

      I can’t really comment on food grade or not, my recommendation would be to make sure that you are happy that it’s safe for human consumption. If it was me then I’d be looking at accepted levels of impurities etc.


  • It’s really exciting reading and I am very impressed about all the effort you put into this project.
    I’m going to make my own coffee after your recipe, but I have 2 questions that I hope you can answer.

    You measure TDS, Carbonate Hardness and alkalinity but you only have a TDS meter? How do you find Carbonate Hardness and alkalinity?
    In your spreadsheet you have both “Desired Hardness” and “Resulting Alkalinity” but both values refer to the same cell in the spreadsheet. Should there not be a 2: 1 relationship here?

    • Hi Allan,

      I used a BWT testing kit and a lot if testing to get the hardness and alkalinity.

      I’ll have a look at the spreadsheet as it’s been a while. Ate you referring to the one on Google docs?


      • Yes, it is the Google docs you are linking to under “What equipment do you need” on this website
        Cheers Allan

  • Robin Southwell
    October 9, 2017 8:27 am

    Dear Spencer,
    At present i am using Matt pergers recipe from barista hustle, but i like to make fresh batches each time eg. not make solutions that sit around for weeks on end. However these recipes use sodium bicarbonate, magnesium sulphate and calcium citrate i use a distiller to make 4litres of distilled water then add the ingredients pro rater to the solution calculations and switch on my magnetic stirrer for a half hour to dissolve then use for espresso and v60.
    when i first discovered this post i thought wow then i thought this could be the holy grail of water for coffee but what a faff! But its been bugging me and being a stickler for perfection i will give it a try. Problem is i’m not great at maths and don’t have the brain power to use your calculations to make a fresh 4 litres each time. i would be so appreciative if you could help with this???
    Also i dont doubt your intellect but when you use the BWT filter wouldn’t it undo all the hardwork in creating the calcium carbonate water as BWT claim to replace the calcium ions with magnesium ones,
    I do hope you reply with a potential calculation also i have tried useing the spreadsheet but i cant enter the calculations
    Have a good day and a nice cup of coffee.

    • Hi Robin,

      You can download the spreadsheet from Google and edit it locally with excel, Google sheets or similar.

      The BWT filters exchange some of the calcium ions for magnesium ions, a mixture of both is desirable in coffee brewing.


  • Hi Spencer,
    are you still usin this water recipe?
    Did you find it better than baristahustle water recipe?

    • Just to add I understand that BH watter is NaHCO3 and MgSO4 which you mentioned in other post as unpredictable results and astringent sweetness.
      I just would like to now if there is taste difference for common man.
      I have 2 more questions:
      1. If I freeze the beans and I have the vacum container. Is it possible to use it for the bubbles to dissipate? I mean to vacum the carbonated water.
      2. Why do yuu filter the final watter mixture? Is it possible to filter the calcium concentrate and then measure the TDS?

      • Hi again 🙂

        Everything on here is my opinion. Other opinions wil vary. There are plenty of people who enjoy the BH water. For me there is a difference but I can’t comment on whether you would notice it.

        1. Not sure exactly what you mean here. If you are referring to using a vacuum to remove the fizz from the carbonated water then I think it’s a bad idea as the CO2 will come out of solution under low pressure. You really need a high pressure to get the CO2 into the water.

        2. Calcium Carbonate varies in soluability, the filtration stage does 2 things here
        a. removes undissolved particles of CaCO3 and anything else in there
        b. the BWT carts replace Ca ions with Mg ions


    • Hi there Marian, I no longer make my own water, I find it too time consuming. I tend to mix up off the shelf bottles to achieve my desired outcome. I’m currently mixing 2 x 1.5L bottles of volvic with 1 x 600ml bottle of glaceu smart water. Works great for spro and brewed.


  • Woodson Gannaway
    August 12, 2018 12:28 am

    Spencer, I feel left dangling here. Feel like giving a brief wrapup? Does (did) this method still give you the best water? How much different? Other observations and/or comments? I’m doing espresso with a simple lever machine on home-roasted Yunnan Province (China) beans. I have found the volvic but not the glaceu smart water here.


  • woodson gannaway
    August 24, 2018 10:11 pm

    Are you saying then, that the carbonation method above isn’t so good after all? Can’t get the ppm of the stuff in the smartwater, can you tell us ? Hoping for a little clarification here.
    Thanks, woodson

    • I never said that…. The carbonation method is my favourite but it’s a lot of messing and with a 2 year old to look after I have other priorities in life 🙂

  • Hi Spencer!
    Great write up, thanks for sharing your experiments! I was just wondering if you ever tried magnesium or calcium-citrate instead of chloride or carbonate?!
    Any experience on this? I’d love to hear your opinion.

  • Great post. I can’t wait to try this! My only question is, how do you know how much calcium is being exchanged to magnesium? Have you measured it? I’ve been trying to find out how much calcium is exchanged for magnesium on BWT’s website but it doesn’t specify. It only says calcium content is reduced.

    • Hi Tom,

      Simple answer is I didn’t. You can buy aquarium water kits that measure calcium and magnesium concentration separately so if you want know then that’s the way.


  • I’ll definitely be purchasing the tests and I’ll post my results when I find out. I’m trying to think of how to make this on a larger scale. Have you experimented with making the calcium water more concentrated or is there only so much that will dissolve in the water? Thanks again!

  • Woodson Gannaway
    August 21, 2019 1:21 am

    Spencer, thanks for the clarification. Hope you let your child be a source of joy for you.


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