Total alkalinity or total hardness?

[EuBrew]

My water report shows total alkalinity as CaCO3 (50ppm) and non-carbonate hardness CaCO3 (72ppm) and total hardness CaCO3 (122ppm). It seems all the water calculators I see are looking for HCO3 and I see the conversion is CaCo3 * 1.22. I just want to verify which CaCO3 is multiplied here, total alkalinity or non-carbonate hardness? My guess is total alkalinity in my case 50ppm * 1.22 = 61 HCO3?

 

[mabrungard]

Total Hardness = Temporary Hardness + Permanent Hardness

Temporary Hardness is almost always equal to Total Alkalinity

Permanent Hardness is also known as non-carbonate hardness.

 

[ajdelange]

My water report shows total alkalinity as CaCO3 (50ppm)

That's unfortunate. Life would be much easier if it were reported as 1 mEq/L (which is how its done in much of the rest of the world).

..and non-carbonate hardness CaCO3 (72ppm) and total hardness CaCO3 (122ppm).

Also leads to confusion. It is usual to report magnesium and calcium as the metals (mg/L), to convert those to ppm as CaCO3 and report the sum. It is quite unusual to report permanent (non carbonate hardness) and total hardness these days.

It seems all the water calculators I see are looking for HCO3 and I see the conversion is CaCo3 * 1.22.

That is unfortunate too as what is really needed for accurate calculation is the alkalinity and pH. The lab measures alkalinity and converts that to bicarbonate usually incorrectly. The spreadsheet, if it is to do its job accurately, then must convert the bicarbonate number back to alkalinity. Fortunately, the errors introduced are usually small.

My guess is total alkalinity in my case 50ppm * 1.22 = 61 HCO3?

Yes. Note that your alkalinity is 50(ppm as CaCO3)/50 = 1 mEq/L and the molecular weight of bicarbonate ion is 61.

Don't pay any attention to my rants. These practices aren't going to change. It does make me feel a little better, however.

 

[rhys333]

I have a question about total hardness. I'm lucky that my city provides both monthly and daily water quality reports. The daily reports are abbreviated to the basics, including alkalinity and total hardness: https://www.epcor.com/products-services/water/water-quality/Pages/daily-water-quality.aspx

My question is this: can I extract my calcium value from the total hardness? Calcium is listed in the monthly reports too, but it and other minerals tend to swing quite a bit due to the river water source.

 

[Silver_Is_Money]

I would guess your calcium to be in the ballpark of 32 ppm. How does this compare with the monthly reports?

 

[rhys333]

I would guess your calcium to be in the ballpark of 32 ppm. How does this compare with the monthly reports?

Closer to 46.

 

[ajdelange]

Looking at the more detailed reports we see that median total hardness is 166 and median calcium hardness is 110 which is 100*110/166 = 66% of the total. These are median values and the calcium fraction may be different at any particualr time. But you can still take a hardness number (e.g. the 160 from the first daily report), convert it to mEq/L (160/50 = 3.2), take 66% of that = 2.112 mEq/L and multiply by 20 to get a rough calcium estimate of 42.24 mg/L.

 

[rhys333]

Looking at the more detailed reports we see that median total hardness is 166 and median calcium hardness is 110 which is 100*110/166 = 66% of the total. These are median values and the calcium fraction may be different at any particualr time. But you can still take a hardness number (e.g. the 160 from the first daily report), convert it to mEq/L (160/50 = 3.2), take 66% of that = 2.112 mEq/L and multiply by 20 to get a rough calcium estimate of 42.24 mg/L.

Thanks AJ. I'll study this tomorrow morning.

 

[Silver_Is_Money]

Does 42 estimated ppm calcium allow for the presence of some quantity of magnesium?

 

[ajdelange]

The report indicates 3.2 mEq/L total hardness of which 2.1 mEq/L (66%) is calcium hardness. The remaining hardness is thus 1.1 mEq/L attributable to divalent and trivalent cations which are not calcium. Among these are iron, manganese, aluminum, strontium, zinc and magnesium. Magnesium will be far and away the largest of these so we assume that 1.1 mEq/L is the magnesium hardness. All of this depends to some extent on how the hardnesses are measured. If actual ion concentrations are measured by ICP or AAS then the calcium hardness would be 50*[Ca++] with [Ca++] the calcium ion concentration in mEq/L. Magnesium hardness would be 50*[Mg++] and total hardness the sum of the two. In an EDTA test magnesium would be precipitated as the hydroxide and the solution titrated with EDTA to determine the calcium hardness which would include strontium, iron etc. Total hardness would then be measured without precipitating Mg first again picking up the trace ions.

 

[rhys333]

Further to my question about estimating calcium from a daily alkalinity report... I'm noticing a trend that I can use to estimate the daily calcium level. By taking the alkalinity number (reported as CaCO3) and multiplying by 0.905, I get a reasonably accurate calcium as CaCO3. I'm able to confirm the trend by comparing historical monthly averages for calcium and alkalinity.

 

[ajdelange]

If you had, for example, a source with fixed relative proportions of the various ions that was subject to variable dilution with a low mineral content source such as rain or snowmelt then that should work very well. Conversely if there were a seasonal incursion of a calcium salt such as might be caused by applying calcium chloride to roadways to melt ice then it would not work so well. But yes, in general, hardness and alkalinity are correlated.

 

[Andre3000]

Further to my question about estimating calcium from a daily alkalinity report... I'm noticing a trend that I can use to estimate the daily calcium level. By taking the alkalinity number (reported as CaCO3) and multiplying by 0.905, I get a reasonably accurate calcium as CaCO3. I'm able to confirm the trend by comparing historical monthly averages for calcium and alkalinity.

As a fellow Edmontonian, I'm hoping you can clarify all this for me (and others).

Reports:
Monthly (detailed): https://www.epcor.com/products-serv...qreportsedmonton/wq-edmonton-october-2017.pdf
Daily: https://www.epcor.com/products-services/water/water-quality/Pages/daily-water-quality.aspx

If you use Bru'n water, and are looking at the Epcor reports, total alkalinity (of say 120, monthly average for October) and ph, you get bicarbonate and carbonate of 145.3 and .5 respectively using the Alkalinity Conversion Calculator. You then enter these in inputs above.

Using the calcium and magnesium inputs on the Ion Concentration Conversion Calculator using 120 CaCO3, you get Ca=48,Mg=29 and Na=9.7 from the Epcor report.

I'm getting the "water inputs are not balanced" error. What am I doing wrong? Thanks.

As an aside, the Ion Concentration Conversion Calculator also gives different values of bicarbonate and carbonate than the above if you use 120 CaCO3 (146,72 vastly different), why is that?

 

[ajdelange]

The 120 number is the alkalinity. It has nothing to do with calcium content. With that level of alkalinity and pH 7.9 bicrbonate is 145.09 and carb9nate 0.61. Calcium hardness of 105 is 2.1 mEq/L which translates to 42 mg/L as the ions and total hardness of 159 as CaCO3 implies 159 - 105 = 54 magnesium hardness which is 1.08 mEq/L for 13.12 ppm Mg++. These, with the sulfate and chloride numbers, give a profile which balances to within 0.024 mEq/L. Can't ask for much better than that.

 

[Andre3000]

The 120 number is the alkalinity. It has nothing to do with calcium content. With that level of alkalinity and pH 7.9 bicrbonate is 145.09 and carb9nate 0.61. Calcium hardness of 105 is 2.1 mEq/L which translates to 42 mg/L as the ions and total hardness of 159 as CaCO3 implies 159 - 105 = 54 magnesium hardness which is 1.08 mEq/L for 13.12 ppm Mg++. These, with the sulfate and chloride numbers, give a profile which balances to within 0.024 mEq/L. Can't ask for much better than that.

Thank you very much! That all makes sense now.

 

[rhys333]

As a fellow Edmontonian, I'm hoping you can clarify all this for me (and others).

Reports:
Monthly (detailed): https://www.epcor.com/products-serv...qreportsedmonton/wq-edmonton-october-2017.pdf
Daily: https://www.epcor.com/products-services/water/water-quality/Pages/daily-water-quality.aspx

If you use Bru'n water, and are looking at the Epcor reports, total alkalinity (of say 120, monthly average for October) and ph, you get bicarbonate and carbonate of 145.3 and .5 respectively using the Alkalinity Conversion Calculator. You then enter these in inputs above.

Using the calcium and magnesium inputs on the Ion Concentration Conversion Calculator using 120 CaCO3, you get Ca=48,Mg=29 and Na=9.7 from the Epcor report.

I'm getting the "water inputs are not balanced" error. What am I doing wrong? Thanks.

As an aside, the Ion Concentration Conversion Calculator also gives different values of bicarbonate and carbonate than the above if you use 120 CaCO3 (146,72 vastly different), why is that?

The problem I was experiencing is that the daily water values can swing wildly, and were doing so at the time I brewed. They report alkalinity but unfortunately don't report the daily changes in ca and mg as well. When I input the daily alkalinity value, it no longer balanced with the monthly levels, resulting the in the same error message you got. In an attempt to get values back in line I compared older charts, using simple algebra to get the 0.905 value. It's not precise by any means (in fact I was going by the seat of my pants), but the numbers seemed to line up more often than not.

The water profile seems to swing wildly in our city, making the monthly values virtually pointless. They're also a few months behind, and swing a lot based on the seasons. The lab tech I spoke with a few weeks ago told me they switch from chemical filtration (something like that) to direct filtration around this time because the water tends to be cleaner. It sends the alkalinity skywards apparently. I've been meaning to get back in touch with him to see if they can add Ca Mg Cl and S04 to the daily reports. I believe they capture some or all of these on a daily basis but don't bother reporting it because nobody has asked for it. They're a friendly and curious bunch though and may be able to accommodate crazy homebrewers.

 

[Andre3000]

The problem I was experiencing is that the daily water values can swing wildly, and were doing so at the time I brewed. They report alkalinity but unfortunately don't report the daily changes in ca and mg as well. When I input the daily alkalinity value, it no longer balanced with the monthly levels, resulting the in the same error message you got. In an attempt to get values back in line I compared older charts, using simple algebra to get the 0.905 value. It's not precise by any means (in fact I was going by the seat of my pants), but the numbers seemed to line up more often than not.

The water profile seems to swing wildly in our city, making the monthly values virtually pointless. They're also a few months behind, and swing a lot based on the seasons. The lab tech I spoke with a few weeks ago told me they switch from chemical filtration (something like that) to direct filtration around this time because the water tends to be cleaner. It sends the alkalinity skywards apparently. I've been meaning to get back in touch with him to see if they can add Ca Mg Cl and S04 to the daily reports. I believe they capture some or all of these on a daily basis but don't bother reporting it because nobody has asked for it. They're a friendly and curious bunch though and may be able to accommodate crazy homebrewers.

That is some great info. This week it looked to be pretty consistent as far as I could tell. How have you been managing the wildly changing chemistry? I figured the monthly reports were good enough.

 

[ESBrewer]

In some locations tap water may be a mixture of waters from two or more departments/facilities and the ratio of these two waters may be changing (constantly adjusted based on water demand/production). I've seen exactly that kind of fluctuation here in Northern Europe with the alkalinity, although it wasn't so big that it would have completely ruined any beers. Something like one department has 50ppm HCO3 and the other had 120ppm and those were mixed randomly. And luckily it is not the case with my own water supply.