"Total Hardness"?

[PeeBee]

A little puzzle I'm having. The following snip is out of a brewing water calculator (Bru'n Water, but makes no difference here):

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Soft water, only 101 ppm total dissolved solids.

54 ppm "Total Hardness" (as CaCO3), 14 ppm (as CaCO3) alkalinity. "Permanent Hardness" should be "Total Hardness" less "Temporary Hardness" (which for UK tap water "Temporary Hardness" will be due almost entirely to "bicarbonate", as will "alkalinity"). Hence 54 - 14 = 40 ppm as CaCO3 ... "Permanent Hardness"!

Except it isn't!

The water authority is reporting "Total Hardness" as the total of Calcium and Magnesium ions in the water (49 ppm of Calcium, five of Magnesium, as CaCO3), and that is "Permanent Hardness". So, add 14 to 54 and you get "Total Hardness" of 68, which ain't "soft"! It would be categorised as "Medium Hard". What gives?



I can only think that water this soft has to be described as "before treatment", because the amount of "dosing" needed to neutralise the acidity of this "mountain runoff" water would skew the report? Perhaps? Doesn't really standup to too much thought as an explanation.

Who's got a better explanation?

[Eric]

Total Hardness is a measure of all calcium and magnesium (plus boron, I think, but so little to make no difference) in water, which includes those in alkaline form, i.e. the temporary hardness.

Now 19.6ppm Calcium provides 49ppm hardness as CaCO3 and 1.22ppm magnesium will give 5ppm hardness as CaCO3, a total hardness of 54ppm as CaCO3.

Assuming the calcium and magnesium that form the alkalinity are in equal proportion to the totals present, then 5.1ppm of calcium and 0.3ppm magnesium of the totals for those ions will form the alkaline part (or alkalinity) in that water.

If I have this right, that water has 5.1ppm calcium and 0.3ppm magnesium associated with carbonate and bicarbonate anions with 14.5ppm calcium and 0.92ppm magnesium associated with other anions.

And that water is soft, with 19.6ppm calcium 1.22ppm magnesium and 8.39ppm carbonate making a total of 29.21ppm, a minority of the total dissolved solids. The balance, in excess of 71ppm will be of sodium, potassium, sulphate, chloride, nitrate, phosphate and potentially other ions.

[PeeBee]

Total Hardness is a measure of all calcium and magnesium (plus boron, I think, but so little to make no difference) in water, which includes those in alkaline form, i.e. the temporary hardness. ...

Thanks Eric. Am I getting a too simplistic idea of "permanent" and "temporary" hardness?

The impression I was getting (in Bru'n Water and in plenty of other sources) is Calcium and Magnesium salts are responsible for Permanent Hardness and Carbonate (Bicarbonate) salts are responsible for Temporary Hardness.

But it's not Calcium and Magnesium salts creating "permanent hardness". Some Web sites define Chloride and Sulphate (and others to a lesser degree) salts causing permanent hardness. Calcium and Magnesium are just the salts to expect as they are commonest in water (monovalent metal salts, like sodium, excluded?).

This makes sense! I couldn't see around the conundrum that both Calcium & Magnesium Carbonate (Limestone) is the main source of carbonates/bicarbonates in water. Which creates both permanent and temporary hardness? ... Nah!


Maybe not the answer you expected me to take away? Maybe it was, but you didn't expect me to be so daft? It's all beginning to add up now!


Here's what has typically mislead me: "The presence of soluble salts of calcium and magnesium ...". Read too quick and it's possible to miss any "soluble" word, where-upon your head is messed up for eons! After all, some miniscule amount of calcium carbonate is soluble in water (I guess it's all down to the CO2 dissolved in the water to create acid). And we were even chucked down caves as school kids and had it explained the limestone was dissolved away by underground rivers (which were standing in!). Teachers don't always realise what they are doing to kids!

[Eric]

It was much more simplistic before the Americans invented modern brewing.

That statement does them a great and undeserved injustice, but water was a lot simpler before modern American Chemical Science combined with Visual Basic and Excel displaced simple basic British Brewing Science.

Firstly it matters not one jot to a brewer if any alkalinity present is carbonate or bicarbonate, the same amount of acid will deal with either. It might be difficult or near impossible to dissolve calcium carbonate in water, but with absolute certainty, calcium bicarbonate can never exist as a solid, making understanding its effect on Total Dissolved Solids more complicated. But hardness is the greatest difference, and it's interplay with alkalinity.

Britain and North America are very different in climate, weather and geology, more than many might appreciate. It is raining while I am writing this and virtually everyone in Britain reading this within a day of it being written will likely have endured the same weather. UK is blessed with regular fresh falls of rainwater, which isn't the case for the rest of the world. UK has a lot of hard water and so does USA too, but there in many places the water supply is more processed, frequently softened by ion exchange which replaces calcium and magnesium by sodium. That isn't done in UK, yet.

The consequence is that while in Britain all alkalinity will likely also form part of the hardness, in USA it can very likely not, and in such cases, no amount of boiling will reduce alkalinity. So maybe, calculators developed in the US could be more complicated than necessary for UK users, which isn't necessarily advantageous when trying to keep matters basic and simple.

[PeeBee]

"Water was a lot simpler". I guess so. All the Americans fault (ignoring your "great and undeserved injustice" remark, I'll go with blaming the Americans on the basis that no-one blames themself for their faults these days).

When I started brewing back in ... (Sorry, my memory has all gone foggy), There was just temporary hardness. Permanent hardness was something they suffered from a million miles away in southern England. I knew I had hard water though 'cos the kettle was furry.

I only learnt later what a furry kettle really meant, the fur in our kettle was what the water board put in the neutralise the aggressively acid "soft" water and stop it rotting the pipes. So, until a handful of years ago, all this "Total Hardness" and "Alkalinity" is new to me (I've always lived in soft water areas). Or that's my (real) excuse for making a hash of my "Hardness" understanding. But I've been corrected now, and when I stop hiding my face in shame, I'll be dishing out dirt ten-fold more intensely on crazy UK water modifying practices . (The practices "borrowed" from the Americans, Australians, etc; i.e. those not living on a little poky island that is).

Cheers Eric!

[Jocky]

While it’s infuriating that the numbers don’t add up, for practical purposes, whether your total hardness is 54 or 68ppm matters not.

14ppm CaCO3 is pretty much the minimum resolution by measurement error when testing alkalinity.

Your effort would be much better placed on other practical brewing efforts in adjacent areas.

[themadhippy]

water was a lot simpler before modern American Chemical Science combined with Visual Basic and Excel displaced simple basic British Brewing Science.

[Eric]

Water is called hard when it's hard to form a lather with soap. Hard water was known before there were water companies, or anyone called a chemist, although brewers existed. It matters not whether the causal ions form part of a salt or alkalinity, their influence on soap is the same. Those raised in hard water areas quickly recognise soft water when a quick splash doesn't remove all soap after a wash or shave.

[PeeBee]

While it’s infuriating that the numbers don’t add up, for practical purposes, whether your total hardness is 54 or 68ppm matters not.

14ppm CaCO3 is pretty much the minimum resolution by measurement error when testing alkalinity.

Your effort would be much better placed on other practical brewing efforts in adjacent areas.

I know. I did place my efforts in other areas.

But I answer the odd forum query, and for dealing with water hardness my knowledge proved lacking. Bit embarrassing really, just won't do! So, my knowledge had to be fixed and that had nothing to do with brewing my beer.

The enormous effort resulted in me paring off ... err ... 2ppm Calcium off my "base water" profile. Wow!

Lots of peripheral tidbits picked up though.


And 14ppm as CaCO3? Minimum resolution when testing alkalinity? Don't I know it! I bought one of those "Salifert" alkalinity tests a few years ago ... what a waste of time, yet everyone was recommending it. It has a resolution of about 30ppm (0.8 or 0.9ish meq/L resolution, 1meq/L = 50ppm). Guess what happened when I tried it!

[PeeBee]

... Soft water, only 101 ppm total dissolved solids. ...

This is what Bru'n Water reports (as TDS) but isn't what my meter will read.

About 65ppm TDS is what I get ... or 101microS/cm (electrical conductivity). Is Bru'n Water right with this?

I'd like to use a TDS meter to pick up potential changes (I get large, slow, swings), they convert to BIG swings in mash pH which I'd like to be pre-warned of. But, mashing at pH4.9 isn't a death nell over brewing.

Exceptionally soft water has its hazards too!

[EDIT: Scrub this! It really is just the addition of the various ions as a total. Near impossible to get wrong, and what I've put in the rest of the Bru'n Water sheets adds up to 101.2. So ... cheap bit of ineffective Chinese tat as a TDS meter? ... Probably!]

[Eric]

... Soft water, only 101 ppm total dissolved solids. ...

This is what Bru'n Water reports (as TDS) but isn't what my meter will read.

About 65ppm TDS is what I get ... or 101microS/cm (electrical conductivity). Is Bru'n Water right with this?

I'd like to use a TDS meter to pick up potential changes (I get large, slow, swings), they convert to BIG swings in mash pH which I'd like to be pre-warned of. But, mashing at pH4.9 isn't a death nell over brewing.

Exceptionally soft water has its hazards too!

[EDIT: Scrub this! It really is just the addition of the various ions as a total. Near impossible to get wrong, and what I've put in the rest of the Bru'n Water sheets adds up to 101.2. So ... cheap bit of ineffective Chinese tat as a TDS meter? ... Probably!]

TDS, Total Dissolved Solids, is exactly as the meaning implies. It was usual procedure to take a measured sample of the particular water, then evaporate liquid (to 180 centigrade if my memory serves me correctly, weigh the residue and calculate in terms of mg/l, TDS. Simple? But things change, don't they?

Pure water won't conduct electricity, but is rarely found in pure form due to its ability to dissolve the overwhelming majority of materials that it will likely make contact in nature. Once adulterated, it will conduct electricity, and the greater the contamination, the more electrical current can flow.

At school, in physics, we learned electrical resistance was measured in OHMS, symbol being the Greek letter Omega, and that 1 amp would pass through a resistance of 1 ohm with a potential difference of 1 volt. We later learned the unit of conductance was mhos and was the mathematical reciprocal of resistance. Today, the mho is replaced by Seimens, "S", and when used for low conducting mediums like our tapwater, is prefixed by the Greek letter Mu for micro, more commonly on our devices with lower case u.

So today, for simplicity(?) we measure the electrical conductivity at 25C in uS/cm and multiply that by, typically, 0.67 and call it TDS, which potentially has similar probability of being correct as picking next weeks lottery numbers. The meter that measures conductivity (or TDS) passes an alternating current (not DC as the diagram did show on the website of the author of the calculator involved here) between two probes to produce whatever it does or is intended.

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The calculator shown indicted the cations total as 1.33meq/L with anions of 1.49Meq?L. Although those are not equal to imply that water cannot exist, those are all we have. So, using those with the figures for calcium, magnesium and carbonate I earlier derived, 5.75ppm sodium would bring the cation total to 1.33 meq/L, while 46ppm sulphate and 9ppm chloride would be a fit and raise the anion total to 1.49 meq/L, but they total only 90, a discrepancy of 11ppm. I wonder?

[PeeBee]

The ion discrepancy in my water report may be far worse than that Bru'n Water clip indicates. Because I "misrepresented" the nitrate content. Originally because I was messing with the "NO3-N" units format (not used in UK?), and latterly 'cos it was a way of "losing" some ion imbalance.

I understand an ion imbalance might indicate an "impossible" water report, but perfect balance would equally be suspicious. Bru'n Water purposely extends the number of items it can report to address balance, nitrate is one fairly common (from farm fertilisers) with no obvious impact on beer. It is also purposely wooly when checking ion balance. Though I wish it would include ions of "umobtanium" and "eludate" anions for the purpose of balancing ions.

Actually ... putting the "right" value in for nitrate (2.3ppm, there ain't much farmland up on those hills!) the balance comes out much better. And me TDS drops marginally!

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[Eric]

Now I'm somewhat confused.If the Anion total previously was 1.49 meq/L and you've since included additional Anion, why has that total reduced to 1.37 meq/L. However, you'll no doubt sort or explain that difference, but your latest posting has revealed the real crux here, that calculator's error in calculating TDS.

From the initial figures supplied,

Now 19.6ppm Calcium provides 49ppm hardness as CaCO3 and 1.22ppm magnesium will give 5ppm hardness as CaCO3, a total hardness of 54ppm as CaCO3.

Assuming the calcium and magnesium that form the alkalinity are in equal proportion to the totals present, then 5.1ppm of calcium and 0.3ppm magnesium of the totals for those ions will form the alkaline part (or alkalinity) in that water.

If I have this right, that water has 5.1ppm calcium and 0.3ppm magnesium associated with carbonate and bicarbonate anions with 14.5ppm calcium and 0.92ppm magnesium associated with other anions.

And that water is soft, with 19.6ppm calcium 1.22ppm magnesium and 8.39ppm carbonate making a total of 29.21ppm, a minority of the total dissolved solids. The balance, in excess of 71ppm will be of sodium, potassium, sulphate, chloride, nitrate, phosphate and potentially other ions.

and

The calculator shown indicted the cations total as 1.33meq/L with anions of 1.49Meq?L. Although those are not equal to imply that water cannot exist, those are all we have. So, using those with the figures for calcium, magnesium and carbonate I earlier derived, 5.75ppm sodium would bring the cation total to 1.33 meq/L, while 46ppm sulphate and 9ppm chloride would be a fit and raise the anion total to 1.49 meq/L, but they total only 90, a discrepancy of 11ppm. I wonder?

But to the real crux,

TDS, Total Dissolved Solids, is exactly as the meaning implies. It was usual procedure to take a measured sample of the particular water, then evaporate liquid (to 180 centigrade if my memory serves me correctly, weigh the residue and calculate in terms of mg/l, TDS. Simple?

The calculator sums all ions to make TDS, but TDS stands for Total Dissolved Solids, not TDI, if such a term as Total Dissolved Ions exists.

Calcium bicarbonate and magnesium bicarbonate can only exist in aqueous form, they cannot exist in solid form and therefore by definition should not be counted as a dissolved solid.

When we heat Ca(HCO3)2, the result is CaCO3 +H2O +CO2 and the solid is calcium carbonate. A brewer doesn't need to differentiate between those two, acid will reduce alkalinity by the same amount whatever form it might exist. A chemist provided with a pH reading might make a prediction of how much of each might exist at standard temperature and pressure.

So, whatever figures you have or use, that calculator overestimates TDS by, a bit more than half the bicarbonate figure. That is because the solid anion consists of one carbon and three oxygen atoms, having lost one carbon, three oxygen and two hydrogen ions while coming out of solution.

[PeeBee]

Now I'm somewhat confused.If the Anion total previously was 1.49 meq/L and you've since included additional Anion, why has that total reduced to 1.37 meq/L. However, you'll no doubt sort or explain that difference, but your latest posting has revealed the real crux here, that calculator's error in calculating TDS. ...

Yeap, I can explain away my part in the conundrum ... 'cos I already have in my last post (not effectively it seems?).

I was messing with the "NO3-N" twaddle and, possibly because it wasn't doing anything damaging to my carry-ons, I absent-mindedly left it there! So, it's only now (3-4 years later?) I notice it and make it proper straight (there's only 2-3ppm nitrate reported, not 10+). I thought I'd chuck in the reported "iron" cation at the same time as knocking off the 8ppm or so "nitrate" anions. But the "iron" is only a tiny fraction, measured in ppb (160 of 'em, which rounded to 0.2ppm without my help).

As for Martin Brungard doing something untoward calculating TDS ... not my argument and I'll keep me 'ead down before things get well above my comprehension! (With "Martin knocking conversations" I always seem to be on the wrong side anyway. Or more accurately, not helping anyone on any side). I'll keep in mind what you're saying about bicarbonate so as to spout it out again in some future recital of my trademark rants (all arse about face no doubt?)


At least I'm getting me Cations and Onions the right way around in this thread?

[Eric]

I thought I'd read and understood your previous post. Let me confess to being busy with a 1 and a 3 year old several days per week, but I cannot blame them if I've got things wrong.

It was the sudden reduction in anions that got me confused and I still cannot see how increasing nitrates, nitrites or whatever aditional anion can reduce the anion total from 1.49 meq/L to 1.37 meq/L.

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As for iron, I doubt it ever finds it's way into water by itself and could invariably form an oxide that most likely won't be measured during analysis, so I'd advise it might not be helpful to count it as in an ion balance check.

In USA, homebrewers mostly use Wards for water analysis, a seemingly reliable company. Their main customer base are farmers, not brewers, so report sulfate, US spelling, in terms of sulphur which can spoil matters for those unaware. More importantly for the brewer they report phosphorus as a cation, but it invariably is present as phosphate, and therefore an anion. As a consequence their cation total usually exceeds anion content in their balance tabulation.

Anyway, you can't blame Martin, the problem must be by the calculator. Some time after getting my first TDS meter, he was advised of my experiences, findings and benefits of owning one. Those included an explanation of what constitutes a solid. I thought that bit got home and later, after his inspired inclusion in his blog of a piece on the benefit of a TDS meter, I did noticed his DC source rather than the accepted AC to avoid build up of deposits on the probes.

You can't win them all.