# Water Unit Conversions



## glenos (3/4/09)

I have had a client ask for some results in degrees German hardness and we work in mg/L and I have been having some trouble finding all the conversions.

what I have is the following:

Our report for will be issued in mg/L, to convert this to dH the follwoing factors apply:
Ca dH = [Ca mg/L] / 7.118 
Mg dH = [Mg mg/L] / 4.317
Alkalinity dH = Alkalinity as CaCO3 mg/L / 17.848 *- I am not sure about this one.*
Hardness dH = Hardness as CaCO3 mg/L / 17.848

We calculate hardness using the following forula:
Hardness as CaCO3 mg/L = 2.497*[Ca mg/L] + 4.118*[Mg mg/L]

So by applying the above factors and doing some internet searching I have come up with the following:

Residual alkalinity dH = Alkalinity dH - Ca dH / 3.5 - Mg dH / 7
Residual alkalinity mg/L = Alkalinity mg/L - Ca mg/L / 1.4 - Mg mg/L / 1.77

I have plugged in a real sample and come up with the following numbers, do they seem right?

ppm	divide by	dH
Ca	32	7.118	4.50
Mg	7.6	4.33	1.76
Alkalinity	110	17.848	6.16
Hardness	111.20	17.848	6.23

RA	82.70 4.63

sorry for the loss of formatting on the table at the end, how do I make it look pretty.


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## jonocarroll (3/4/09)

Does this help? Unit coversion can also be found here.

Note that I didn't quote the whole post just to reply to it, people??? That's next in line for getting on my nerves


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## Adamt (3/4/09)

Your calculations look right, I think!

:icon_offtopic: 



QuantumBrewer said:


> Does this help? Unit coversion can also be found here.
> 
> Note that I didn't quote the whole post just to reply to it, people??? That's next in line for getting on my nerves



+1


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