Total Hardness Digital Titrator ® Method - Hach APA 6000 Operation Manual

5.3.1 Total Hardness Digital Titrator
1. If a Digital Titrator
is used, fill a clean and
empty titration cartridge
with Reagent 3.
5. Using the volumetric
pipet, transfer the sample
volume from Table 10 into
a clean 250-mL
Erlenmeyer flask.
9. Swirl the flask while
titrating with Reagent 3
from red to pure blue.
6200018bench.fm
®
Method
2. Insert a clean delivery
tube into the titration
cartridge. Attach the
cartridge to the titrator
body.
6. Dilute to about the
100-mL mark with
deionized water.
10. Record the number of
digits required.
(
Sample Concentration mg/L as CaCO
3. Turn the delivery knob
to eject a few drops of
Reagent 3. Reset the
counter to zero and wipe
the tip.
7. Using a marked
dropper, add 1 mL of
Reagent 1. Swirl to mix.
11. Calculate the sample
concentration using the
equation below:
×
125 Digits Required
)
= --------------------------------------------------------------------------------------------------------------------- -
3
Sample Volume (mL)
Testing Samples for Total Hardness
Section 5
Refer to Table
10 on page 24.
4. Refer to Table 10 to
choose the size of the
volumetric pipet,
depending on sample
concentration.
8. 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 then
be kept for approximately
3 months.
× ( )
Reagent 3 Titer M
Page 25