As an example, suppose the drinking water supplied to animals has the following analysis. The LSI index is calculated at two temperatures: 25^{o}C (room temperature) and 82^{o}C (cage wash cycle). The colder incoming water will warm to room temperature in the manifolds. Residual water in the rack manifold can be heated to 82^{o}C when the rack is in the cage washer.
Water Analysis:
LSI Formula:
LSI = pH - pH_{s}
pH_{s} = (9.3 + A + B) - (C + D) where:
A = (Log10[TDS] - 1)/10 = 0.15
B = -13.12 x Log10(^{o}C + 273) + 34.55 = 2.09 at 25°C and 1.09 at 82°C
C = Log10[Ca^{2+} as CaCO_{3}] - 0.4 = 1.78
D = Log10[alkalinity as CaCO_{3}] = 1.53
Calculation at 25^{o}C:
pH_{s} = (9.3 + 0.15 + 2.09) - (1.78 + 1.53) = 8.2
LSI = 7.5 - 8.2 = - 0.7
Hence No Tendency to Scale
Calculation at 82^{o}C:
pH_{s} = (9.3 + 0.15 + 1.09) - (1.78 + 1.53) = 7.2
LSI = 7.5 - 7.2 = + 0.3
Hence Slight Tendency to Scale
See also: Calcium carbonate, Carbon dioxide, Chlorination, Dissolved oxygen, Langelier calculation, Langelier index, Larson-Skold index, Oddo-Tomson index, pH, Puckorius index, Ryznar index, Scaling Indices, Stiff-Davis index, Total dissolved solids, Water corrosivity