7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Table of Contents
1. Set up
2. Calibration
a. pH
b. Specific Conductivity
c. Water Saturated Air Dissolved Oxygen
d. Rhodamine [ppb]
e. Chlorophyll a [µg/L]
f. Depth (25m)
g. Turbidity Self Cleaning
3. Launching
4. Maintenance
5. Storage
1
2
5
7
8
9
11
13
15
16
19
23
24
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Set up
1. Start Hydras 3 LT software
2. Attach Sonde to computer via calibration cable and USB to serial
connector.
3. Start Hydras 3 LT software
2
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
4. Scan for sonde
a. If Hydras does not locate sonde, click Re-Scan for Sondes button
until sonde is recognized.
3
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
5. Select Hydrolab DS5/44844, and press Operate Sonde
4
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
6. Select Calibration Tab
5
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Calibration of each sensor should be preformed in the following manner to
ensure accuracy and to prevent contamination.
6
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
pH
1. Select the pH tab.
2. Triple rinse the calibration cup with DI water
3. Rinse the cup with calibration solution pH 7.
Note: pH is a two-point or three-point calibration. A pH standard between 6.8 and 7.2 is treated
as the “zero” and all other values are treated as the “slope”. First calibrate “zero”, then calibrate
“slope”.
4. Pour the pH or ORP standard to within a centimeter of the top of the cup.
5. Under Cal Point 1, enter 7.00 into pH [Units] field
1. Once the current Value stabilizes, press the Calibrate button.
6. Triple rinse with DI water
1. Rinse with pH 4 standard
2. Pour the pH 4 standard to within a centimeter of the top of the cup.
3. Change Cal Point to 2 and input 4.00 in pH[Units] field
4. Once the current Value stabilizes, press the Calibrate button.
7. Repeat with pH 10 standard
7
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Specific Conductivity
Note: TDS measurements are based on specific conductance and a user-defined scale factor.
The factory default scale is 0.64 g/L / mS/cm.
This procedure calibrates TDS, raw Conductivity, and Salinity. Specific conductance requires a
two-point calibration. Calibrate the sensor to zero and then to the slope buffer.
1. Determine sampling range ( mS/cm or μS/cm)
a. Select appropriate tab for range
2. Triple rinse cup with DI water.
3. Fill cup with DI water and enter 0.00 into SpCond field
4. Wait for sensor to stabilize and press Calibrate button
5. Rinse cup with conductivity standard
6. Pour the specific conductance standard to within a centimeter of the top of the
Calibration Cup
7. Make sure there are no bubbles in the measurement cell of the specific
conductance sensor
8. Enter the SpCond standard for mS/cm or μS/cm into SpCond field
9. Wait for sensor to stabilize and press Calibrate button.
8
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Water Saturated Air Dissolved Oxygen
1. Click the Calibration tab and select the LDO [SAT] tab.
Note: It is important to maintain temperature stability during calibration. Care should be taken to
keep the sonde out of direct sunlight or away from any other energy/heat source which will cause
the temperature in the calibration cup to change during calibration. A reflective sun-shield is
recommended if no natural shade is available. If the temperature in the calibration cup changes
more than 0.5 °C during the calibration, it is recommended to recalibrate the sensor.
2. Triple rinse with DI water.
3. Calibrate the sensor using temperature-stabilized air-saturated water. In a
laboratory environment this is typically done by allowing water to
equilibrate at least 12 hours after being run from a faucet or decanted from
an opened water bottle.
4. Seal the bottle and shake it very vigorously for 40 seconds.
5. With the sonde positioned with sensors facing upright, pour the water into
the calibration cup, fully submersing the Hach LDO sensor cap and the
temperature sensor (Figure 3). Make sure the water comes close to the
top of the calibration cup. Place the calibration cup cap upside down
(concave upward) on top of the calibration cup to cover the calibration
cup.
Note Do not tightly seal or otherwise raise the barometric pressure in the calibration cup. Make
sure that the calibration cup is not in direct sunlight or in the presence of a heat or light source
that could change the temperature in the calibration cup.
6. Determine the barometric pressure for entry as the calibration standard.
The barometric pressure needs to be in mmHg.
1mmHg = 0.00133322 bar
1mmHg =133.322 Pascal
1mmHg = 0.019336778 pounds/square inch [absolute].
7. Enter barometric pressure in LDO_BP [mmHg] field.
8. Wait for sensor to settle and click Calibrate button.
9
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
10
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Rhodamine [ppb]
(Method 1)
1. Click Parameter tab and select Rhodamine [ppb].




0 = Auto gain
(In most cases, it is recommended to leave the sensor in auto
gain mode for maximum dynamic range.)
X1 gain provides a range of 0 to 1000 ppb
X10 gain provides a range of 0 to 100 ppb
X100 gain provides a range of 0 to 10 ppb
2. Input the appropriate gain for experiment into Range [Range] field.
3. Click Save Settings button.
11
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
4. Select Calibration tab, and select Rhodamine[ppb]
5. Triple rinse the calibration cup and sensors with DI water.
6. Fill calibration cup with DI water, and allow sensor to settle.
a. This is a 0 ppb solution for Rhodamine.
7. Enter 0.00 into the Rhodamine [ppb] field and click the Calibrate button.
8. Fill the calibration cup with a known concentration (ppb) of Rhodamine,
enter the concentration in the Rhodamine [ppb] field and click the
Calibrate button.
12
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Chlorophyll a
(Method 1)
1. Click Parameter Setup tab, and select Chlorophyll [µg/L].
2. Input a gain of 0 into the Range [Range] field.
3. Click Save Settings button.
13
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
4. Click the Calibration tab and select Chlorophyll μg/L.
5. Triple rinse the calibration cup and sensors with DI water and fill with DI
water.
6. Input 0.00 into the Chlorophyll [μg/L] field and click the Calibrate button.
7. Fill calibration cup with a know concentration of Chlorophyll (ppb) and
enter the concentration into the Chlorophyll [μg/L] field.
8. Wait for sensor to settle and press the Calibrate button.
14
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Depth (25m)
1.
2.
3.
4.
Triple rinse calibration cup with DI water.
Fill cup above sensor with DI water.
Enter 0.00 in Dep25 [meters] field.
Wait for sensor to settle and click Calibrate button.
15
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Turbidity Self Cleaning
1. Click on the Calibration tab and select Turbidity [Rev].
2. Select number of rotations in Turbidity [Rev] field.
3. Click Calibrate button.
16
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
4. Click on the Calibration Tab and select Turbidity NTU.
5. Triple rinse calibration cup and sensor with DI water.
6. Remove the wiper from the unit. Store the removed wiper in turbid-free
water for reinstallation (Figure 1).
7. Rinse the sensor with DI water, and dry with lint free cloth.
a. To prevent excess bubbles, slowly pour the standard down the side
of the cup.
8. Enter calibration point in Turbidity [Point] field.
9. Enter StablCal standard value in Turbidity [NTU] field.
10. Wait for sensor to settle (30 seconds) and click Calibrate button.
11. Triple rinse sensor with DI water, and dry with lint free cloth.
12. Repeat with each StablCal standard solution.
a. After a successful calibration, "Calibration completed!" will be
displayed. If
"Calibration failed…" appears, then that point must be recalibrated.
13. Replace wiper (Figure 1)
17
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
18
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Removing the Wiper
1. Carefully loosen the set screw holding the wiper on the motor shaft and
remove the wiper.
Installing the Wiper
1. Place the wiper assembly on the shaft with the set screw aligned with the
flat on the wiping shaft.
2. Gently press the wiper arm down until the wiper arm hits the stop on the
shaft. The wiper pad should be compressed to approximately one half the
original thickness.
3. Tighten the set screw. It is important that the wiper arm body does not
make contact with the probe face—only the pad should be in contact. A
gap of .5 mm (0.02 in.) between the wiper arm and the optic surface is
typical when a new pad is installed.
19
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Launching
1. Click the Settings tab
2. Within the Log Files area, select desired sampling interval from the
dropdown Files field
20
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
1. Select the Log File tab, then click the Create Button
Note: Log files may not be written if the sampling time set under the Settings tab is too high.
3. Input log file name; press OK
4. Select the filename in the Log File Field
5. Input Parameters, logging interval, Sensor Warmup, and Circulator
Warmup values into the respective fields
6. Input desired start and stop times into the Start Logging and Stop
Logging fields
7. Click the Save Settings button
8. Click Enable button to launch sonde
9. Click Disable button to stop logging
21
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
22
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Maintenance
Directly following each use the sonde should be inspected for wear and damage.
Special attention should be taken to insure that the sensors have not been
fouled.
1. Remove the weighted sampling cap
2. rinse sensors using DI water
3. Inspect each sensor taking note of any wear on the body or working
surface
a. Flush the entire instrument with clean fresh water. Use soapy water
and a soft brush to clean the outside surfaces of the instrument.
b. Soak the entire instrument in freshwater for at least 30 minutes.
c. Visually inspect the optical windows. Use optical tissue or a cotton
swap with soapy water to clean the optical windows. Rinse with
freshwater.
d. Record any damage to the sensors
Note: Never use organic solvents or strong acids or bases
23
7/31/2017
Hydrolab Calibration SOP
Modified by Chris Butler
Storage
Sonde should be inspected for physical damage and/or wear after each
deployment; taking note of any damage to body or sensors. Rinse and fill the
calibration cup with 1 inch of DI water. Prevent sensors in an area where
freezing will not occur.
Return all plugs into positions, and keep electrical cables coiled in a plastic
container. Coils should not be any tighter than 6 inches in diameter.
24