YSI 9300 Photometer - Manual (Page 106)

NOTE
The expression of alkalinity results sometimes causes confusion. It is normal
practice to express the result as mg/l CaCO
3
(calcium carbonate). This is merely a
convention to allow the comparison of different results and does not necessarily
indicate that the alkalinity is present in the water in this form. The different
chemical forms of alkalinity have been referred to in the test instructions.
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