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Water adjustment

Romanos_P

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Hi,

I got a specification from my water supplayer. And it says that I have Water Hardness - 63 mg/dm3 and Mg - 10,2. When I put Mg into BS Water Profile, I have to put 80 ppm of Ca to achieve 63 ppm effective hardness. Do I do it correct? I have doubts becouse I've calculated Ca level at 8,35 for these values from formula: (Ca/20 + Mg/12,1)x50 = Wh (Water Hardness).

How is BS calculating effective hardness?

 

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So, just a quick look, I would think that your supplier is misnaming hardness as alkalinity. BS says alkalinity = 63 ppm, your water report says hardness = 63 ppm. I would believe BS.
 
No. It's just coincidence - Alikalinity is related to HCO3 directly in BS. To be honest, I don't have this value from supplier. I put 77 becouse I read somewhere that this is most common value. But as I said its not ralated to water effective hardness in BS.
 
so water hardness is related to Ca and Mg, and with your numbers, your water hardness is very low, in other words you have very soft water.
 
The point is that I don't know the Ca value. I know only Mg and water main hardness according to my supplier.

When I calculate using the formula I wrote earlier i have Ca = 8,35 - it's less then Mg!!! But when I put this quote (8,35) to BS I have 12ppm wtaer hardness. So I have to put Ca = 80 ppm to achieve hardness = 63ppm. But I dont know if its the same hardness :/ So I've asked - How BS is calculating its water effective hardness? Is it water main hardness?
 
what are the units they report for your hardness?  There are several measures, but the most common is as CaCO3 (Calcium Carbonate). 

If this is the case, the calculation should be ppm CaCO3 = 2.5 [Ca++] + 4.1 [Mg++] where the 2.4 and 4.1 are the ratio of molar mass as compared to CaCO3.  Plugging the numbers they gave you, 63 ppm CaCO3 = 2.5 * [Ca++] + 4.1 * 10.2 ==> 63 = 2.5 * [Ca++] + 41.82  ==> 21.18 = 2.5 [Ca++]  ==> Ca++ = 8.5 ppm.  Which is pretty close to your calculation.

But that assumes that the hardness is as CaCO3.  If this were German Degrees Hardness (degree d), then one degree hardness would equal 17.8 ppm CaCO3; if French Degrees Hardness, then a degree f would equal 10 ppm CaCO3.  Units of reporting matter a whole lot.
 
the units are mg/dm3. So what is the probability that this is CaCO3 mg/dm3?

 
Then you would need to convert it to ppm as CaCO3 before back calculating your Ca++ concentration (less the Mg contribution).
 
This is why I got the brewers kit from Ward Labs. It returns just the values needed with no guessing.
 
Romanos_P said:
If its in Ca++ I should take it x2.5 to get CaCO3 mg/dm3 right?

The short answer is yes. 

Long answer is that if you are just guessing at what the value means, then it is purely a shot in the dark.  It I had received a water test or test values from some water treatment facility if I had a common supply and the values were not specific in terms of the units, I would call/write/email to get clarification.  Worst case scenario is to find a company which will do water quality testing, as Kevin recommends above, specifically looking at the values which brewer's need for water adjustments. 
 
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