Langelier Saturation Index (Lsi) Calculation; Introduction; Test Procedure; Test Result - MERCK LSI Kit Guide De Référence Rapide

Langelier Saturation Index (LSI)
Calculation

Introduction

Langelier Saturation Index is automatically calculated with 5 parameters measured in feed
waters.
Parameters:
1 Hardness (obtained by the test in Standard Kit, Cat. No. 5.31079.0001)
2 Alkalinity
3 pH
4 Temperature (obtained by the test in Standard Kit, Cat. No. 5.31079.0001)
5 Conductivity (obtained by the test in Standard Kit, Cat. No. 5.31079.0001)

Test procedure

This test is based on ASTM standard calculation procedure (D3739-94).
1. Obtain the measurement of 5 parameters.
2. Open the file "LSI Cal.xls" (available in ManGo No. 20121986).
3. Fill the "Value" column with the measurement result.
Use tool buttons when any values are not available (Calcium Hardness, pH, CO
be obtained by conversion).
4. Set tentative RO stage recovery set point.
5. Check if RO drain LSI is < 1 while Progard contains polyphosphate antiscalant,
at given instantaneous condition.
6. Refer to "At a Glance" page for recovery compatibility with variable temperature range.
7. Check RO permeate parameters. conductivity < 100 µS/cm, Total hardness < 1.5 ppm
and FCE < 120 µS/cm.
Feed water
parameters
Conductivity
Total Hardness
Calcium Hardness 280 ppm as CaCO
Alkalinity
pH
CO
2
Temperature
Feed LSI
Only Total Hardness available
CO2 value missing
pH value missing

Test result

This test is based on ASTM standard calculation procedure (D3739-94).
Release 07/2015
Value Unit System condition (RO drain)
RO stage recovery
600 µS/cm
Drain LSI criteria
350 ppm as CaCO
3
3
250 ppm as CaCO
3
7.4
19.85 ppm
15 °C
0.07
LSI calculation sheet
Water Analysis Kit - LSI Kit
RO drain
parameters
0.5
Conductivity
1
Total Hardness
Calcium Hardness 554.4 ppm as CaCO
Alkalinity
pH
RO drain LSI
RO permeate
parameters
Conductivity
Total Hardness
(example)
Calcium Hardness
CO
2
FCE
en
can
2
Value Unit
1188 µS/cm
693 ppm as CaCO
3
3
495 ppm as CaCO
3
7.70
0.91
Value Unit
17.9 µS/cm
1.0 ppm as CaCO
3
0.8 ppm as CaCO
3
19.9 ppm
73.3 µS/cm
7