Clarification on Alkalinity units in water profile

[Wayne Schroeder]

I fear I have been doing water calcs wrong by entering my water profile incorrectly. Ions are fine, but the alkalinity "as" either "Bicarbonate - HCO3" vs "Hardness - CaCO3" is *maybe* confusing me? My water report contains the following two separate items:
ALKALINITY, CACO3 STABILITY: 60.2
HARDNESS, CARBONATE: 123

Specifically, after reading more on water reports and searching, I believe the ALKALINITY can be expressed either as HCO3 or CaCO3, but the HARDNESS is a different measurement (albeit related). What I think I've been doing is putting the HARDNESS from the water report in as ALKALINITY CaCO3 because the drop down says "Hardness," so now I am concerned that I have been using the wrong value.

The final question here is: Does the Alkalinity value represent Alkalinity OR Hardness from a water report based on which selection you make, or does it always represent Alkalinity expressed as Bicarbonate or CaCO3 stability?

 

[Yooper]

I fear I have been doing water calcs wrong by entering my water profile incorrectly. Ions are fine, but the alkalinity "as" either "Bicarbonate - HCO3" vs "Hardness - CaCO3" is *maybe* confusing me? My water report contains the following two separate items:
ALKALINITY, CACO3 STABILITY: 60.2
HARDNESS, CARBONATE: 123

Specifically, after reading more on water reports and searching, I believe the ALKALINITY can be expressed either as HCO3 or CaCO3, but the HARDNESS is a different measurement (albeit related). What I think I've been doing is putting the HARDNESS from the water report in as ALKALINITY CaCO3 because the drop down says "Hardness," so now I am concerned that I have been using the wrong value.

The final question here is: Does the Alkalinity value represent Alkalinity OR Hardness from a water report based on which selection you make, or does it always represent Alkalinity expressed as Bicarbonate or CaCO3 stability?

View attachment 31776

I'd use the carbonate hardness (CaCO3) if you don't know the HCO3 level.

 

[Wayne Schroeder]

I'd use the carbonate hardness (CaCO3) if you don't know the HCO3 level.

But that is the confusion. I have TWO "CaCO3" numbers, one for Hardness, and one for Alkalinity. The "HARDNESS, CARBONATE" is a CaCO3 number, as is the ALKALINITY, but since they're different things, the numbers aren't the same. It seems to me that the drop down should not say "Hardness" if it wants an alkalinity, because, as I understand it, they are not the same, even though they can use the same units.

Carbonate hardness should not be confused with a similar measure Carbonate Alkalinity which is expressed in either [milli[equivalent]s] per litre (meq/L) or ppm. Carbonate hardness expressed in ppm does not necessarily equal carbonate alkalinity expressed in ppm.

The above is from https://en.wikipedia.org/wiki/Carbonate_hardness.

The water report I'm looking at says the following:

 

[Wayne Schroeder]

I guess the bottom line is does the water profile editor always want alkalinity or does it "switch to asking for hardness" if you change it to CaCO3, because that's confusing to ask for Alkalinity and then label one choice Hardness.

EDIT: May have answered the question myself. If I pull up any of these water profiles in the water calculator, it never mentions hardness, just alkalinity as CaCO3. If this is the case, then I think my chief observation is the term "HARDNESS" in the water profile editor has definitely caused me to use my CaCO3 hardness from the water report in the past and I would advocate for the word HARDNESS to be removed from the profile editor.