I am looking at the water report recieved, and using various spreadsheets to perform calculations (mainly because I am curious at this point). I am coming up with some variances in Alkalinity that don't seem to make sense. Here is what the water report has.

Bicarbonate 42

Calcium 26

Chloride 83

Magnesium 18

Sodium 170

Sulfate 310

Total Alkalinity as CaCO3 72

pH 9.2

From Palmer's book and Martin Brungard's Bru'n Water spreadsheet, it seems like Total Alkalinity as CaCO3 should be much lower, around 34.4 (42/61*50), expressed as a function of bicarbonate. Or Bicarbonate should be around 88.

Am I misunderstanding this relationship or is this a possible error?