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Hardness Ca
CALCIUM HARDNESS
SPECIFICATIONS
Range
0.00 to 2.70 mg/L
Resolution
0.01 mg/L
Accuracy
±0.11 mg/L ±5% of reading at 25 °C
Typical EMC
±0.01 mg/L
Deviation
Light Source
Tungsten lamp with narrow band interference filter @ 525 nm
Method
Adaptation of the
Standard Methods for the Examination of Water and Wastewater,
18
th
edition, Calmagite method. The reaction between calcium and reagents causes a
reddish-violet tint in the sample.
REQUIRED REAGENTS
Code
Description
Quantity
HI 93720
A
-0
Ca & Mg indicator
0.5 mL
HI 93720
B
-0
Alkali solution
0.5 mL
HI 93720
C
-0
EGTA solution
1 drop
REAGENT SETS
HI 93720-01
Reagents for 100 tests
HI 93720-03
Reagents for 300 tests
For other accessories see page 132.
MEASUREMENT PROCEDURE
• Select the
Calcium Hardness method using the procedure
described in the
Method Selection section (see page 12).
• Rinse a graduated beaker several times with unreacted
sample, before filling it to the 50 mL mark with the
sample.
• Add 0.5 mL of HI 93720A-0 Calcium indicator solution
and swirl to mix.
• Add 0.5 mL of HI 93720B-0 Alkali solution and swirl to
mix. Use this solution to rinse 2 cuvettes before filling
them up to the 10 mL mark.
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