If TDS is unknown, but conductivity is, one can estimate mg/L TDS using a conversion table such as the one presented here.
Conductivity |
TDS |
|
( micro-mho/cm) |
(mg/L as CaCO3) |
|
1 |
0.42 |
|
10.6 |
4.2 |
|
21.2 |
8.5 |
|
42.4 |
17.0 |
|
63.7 |
25.5 |
|
84.8 |
34.0 |
|
106.0 |
42.5 |
|
127.3 |
51.0 |
|
148.5 |
59.5 |
|
169.6 |
68.0 |
|
190.8 |
76.5 |
|
212.0 |
85.0 |
|
410.0 |
170.0 |
|
610.0 |
255.0 |
|
812.0 |
340.0 |
|
1008.0 |
425.0 |
Some other saturation indices that have found wide acceptance:
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