B'run Water double check please

[Braufessor]

just updating my B'run Water and second guessing myself. I just want to make sure I have everything entered correctly and am not screwing anything up. I included my ward lab #'s and Water Input screenshot.... Am I missing anything? Thanks

My Ward Lab #'s are:
pH 8.0
Total Dissolved Solids (TDS) Est, ppm 286
Electrical Conductivity, mmho/cm 0.48
Cations / Anions, me/L 5.7 / 5.4


Sodium, Na 6
Potassium, K 2
Calcium, Ca 63
Magnesium, Mg 23
Total Hardness, CaCO3 253
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 12
Chloride, Cl 3
Carbonate, CO3 10
Bicarbonate, HCO3 277
Total Alkalinity, CaCO3 243

 

[Braufessor]

I see one mistake already.... I had to multiply my sulfate and Nitrate..... which I now did.

Do I need to do anything with Line 14????? It says to use those numbers in the table above? Do I actually need to do that since I had an actual Bicarbonate and Carbonate # on the report?

Thanks

 

[mchrispen]

With that last change it looks good.

Line 14 is useful to estimate carbonates when a muni supply only provides alkalinity.

 

[ajdelange]

It says to use those numbers in the table above? Do I actually need to do that since I had an actual Bicarbonate and Carbonate # on the report?

Always use the alkalinity number as that is what the lab measures. Bicarbonate and carbonate are calculated from alkalinity and pH and as you can see from the Ward Labs reported values they do so incorrectly. The correct values are 294.0 for the bicarbonate and 1.62 for the carbonate assuming that the titration end point for the alkalinity measurement was 4.4. We'll forgive them for using ideally dilute chemistry which would give 294.8 and 1.22 respectively for bicarbonate and carbonate. I hope this report is from more than about a year and a half ago as I pointed this out to them in about that time frame.

Please note that this problem with Ward Labs only pertains to samples with pH 8 and above and that I thought they had fixed it when I discussed it with them. One seldom sees pH that high so I haven't been able to check. If this is a recent report that's not so good.

 

[Braufessor]

The report is about 1 year old - this time last year....... I try to send water in every year or two.

The report I had before this one gave me the following #'s:
pH 7.6
Bicarbonate 249
carbonate .5
Total Alkalinity 192

All the other numbers were very similar. I think that report was from 2012 maybe

Perhaps I should send another sample in and see if they have changed any of their methodology, and to just get updated #'s.

 

[ajdelange]

At pH 7.6 < 8 this problem shouldn't emerge but for alkalinity of 192 and pH 7.6 the bicarbonate is 233.7 and carbonate 0.4 (ideally dilute chemistry). Can't explain this one but it reinforces the idea that you should always use the alkalinity number provided you know that your spreadsheet correctly calculates bicarbonate and carbonate. In fact it needs to calculate neither to do charge balance calculations but I think the numbers are of interest to most.

 

[Braufessor]

Thanks.

I will probably send in another sample as I am reexamining my water treatment, updating recipes, changing some to updated spreadsheet, etc..... might as well start with the most recent numbers I can.