Reference> Common Zero Calibration And Span Calibration <Residual Chlorine - horiba TW-150 Instruction Manual

4 CALIBRATION
4.8.2 <Reference> Common zero calibration and span calibration
<residual chlorine>
MEASUREMENT screen
See "4.3 Displaying the Calibration Screen" (page 23).
Preparation

Calibration tank...1

Span standard solution...1 L (Pour the solution into the calibration tank)

Used fluid tank (Install it so that used fluid goes into the tank)

Calibration procedure

Perform calibration in the order: common zero calibration → span calibration.
<Reference> Making residual-chlorine span calibration solution

Sodium hypochlorite standard solution
Sodium hypochlorite
HORIBA pH 7 standard solution (No. 150-7)
Put 35 L of commercial sodium hypochlorite solution (approximate) into a 1000 mL flask, add
approximately 0.34 g of HORIBA pH 7 standard solution powder (Cat. No. 150-7), and then fill
it with purified water up to the gauge line. Use this solution to determine the residual-chlorine
value according to the procedure in JIS-K0101.
Note
The amount of sodium hypochlorite mentioned above is an approximate amount. Sodium

hypochlorite concentration varies depending on reagent manufacturers and storing conditions.
Adjust the loadings so that the residual chlorine concentration is within 2 mg/L.
Adjust the loadings of potassium chloride and pH adjuster so that the values of the pH and

conductivity in the calibration solution match the sample water. Titrate the calibration solution
based on the iodometric titration flow method in JIS-K0101 and determine residual-chlorine
concentration.
64
[CAL.]
CALIBRATION screen
Reagent
[FRC.]
FRC. CAL. screen
Approximate amount
35 L
0.34 g