Total Hardness Buret Method - Hach APA 6000 Operation Manual

Section 5

5.3.2 Total Hardness Buret Method

1. If a buret is used, fill
a 25-mL buret with
Reagent 3.
5. Using a marked
dropper, add 1 mL of
Reagent 1.
Swirl to mix.
9. Calculate the sample
concentration using the
equation below:
(
Sample Concentration mg/L as CaCO
Page 26
Testing Samples for Total Hardness
Refer to Table
11 on page 24.
2. Refer to Table 11 to
choose the size of the
volumetric pipet,
depending on sample
concentration.
6. Using a graduated
cylinder, add 8 mL of
Reagent 2. Swirl to mix.
Note: Prepare Reagent 2 by
mixing one bottle of Indicator
Powder into 1 L of Buffer
Solution. Reagent 2 can be
kept for approximately 3
months.
×
100000 Volume Required mL
)
= -------------------------------------------------------------------------------------------------------------------------------------------------
3
3. Using the volumetric
pipet, transfer the sample
volume from Table 11 into a
clean 250-mL Erlenmeyer
flask.
7. Swirl the flask while
titrating with Reagent 3
from red to pure blue.
( ) ×
Reagent 3 titer M
( )
Sample Volume mL
4. Dilute to about the
100-mL mark with
deionized water,
if necessary.
8. Record the volume
required.
( )
6200018bench.fm