Langelier Saturation Index

(USE WITH “SATURATION INDEX” PROBLEMS)

TOTAL ALKALINITY Factor   +   pH   +   CALCIUM HARDNESS  + TEMPERATURE  –  TDS

SATURATION INDEX PROBLEMS

(Use Printable Langlier Saturation Index for these Problems)

1. Total alkalinity = 50 ppm; pH = 7.0; Calcium Hardness = 200 ppm & Temperature = 76°F.  What is the saturation index value?
2. Total alkalinity = 75 ppm; pH = 7.6; Calcium Hardness = 300 ppm & Temperature = 84°F.  What is the saturation index value?
3. Total alkalinity = 150 ppm; pH = 8.0; Calcium Hardness = 400 ppm & Temperature = 94°F.  What is the saturation index value?

CALCULATION RESULTS

CORROSIVE WATER = < -0.3 CARBONATE SCALE = > +0.3
BALANCED WATER  = – 0.3 to + 0.3

ANSWERS

1. ALKALINITY Factor +   pH   +   CALCIUM HARDNESS Factor   +   TEMP.  Factor   –   12.1

1.7 + 7.0 + 1.9 + 0.6 – 12.1

Saturation Index  =  -0.9         (Water is Corrosive)

2. ALKALINITY Factor +   pH   +   CALCIUM HARDNESS Factor   +   TEMP.  Factor   –   12.1

1.9 + 7.6 + 2.1 + 0.7 – 12.1

Saturation Index  =  +0.2        (Water is Balanced)

1. ALKALINITY Factor +   pH   +   CALCIUM HARDNESS Factor   +   TEMP.  Factor   –   12.1

2.2 + 8.0 + 2.2 + 0.8 – 12.1

Saturation Index  =  +1.1        (Water is Scale Forming)