SmarTroll Calibration and Use
SmarTroll is used to measure temperature, pH, conductivity, dissolved oxygen and depth. The conductivity can be used to determine the total dissolved solids (TDS) also.
- Connect multiprobe to the battery pack and turn on the battery pack and handheld device
(e.g. tablet or phone).
- Open the iSitu app on the handheld.
- Select a location for calibration, such as the lab or your home (You may need to select
a new site on the bottom right)
- It will take an initial reading
- Select flask icon at the bottom of the screen to start calibration
- Note: The DWQ recommends rinsing the conductivity probe with Deionized (DI) water, followed by a gentle dry with a lint free paper towel.
Start conductivity calibration. Use a standard close to what you expect the water body you are testing to be (we usually use 718μS/cm or 1413 μS/cm). Record the standard value and expiration date on the calibration sheet.
- Rinse calibration cup once with DI water and three times with the appropriate standard.
- Add conductivity standard to the fill line and select “Start” at the bottom of the screen
- It may detect the calibration standard being used, but if not type it in
- When reading is stable, record the pre-calibration reading then select “Accept”.
- Go back to the main screen and ensure the conductivity is reading the current calibration standard and record that as the post calibration reading.
- Discard the calibration standard and rinse the probes and cup with DI water
- Go back to the main calibration page
In most environments in Utah, a 2-point with pH 7 and pH 10 is sufficient. If expected value is less than pH 7, use a pH 4 and pH 7.
Record the standard values and expiration date on the calibration sheet.
- On the handheld, select pH calibration, then “2-point-calibration”. (If you are using a 3-point calibration, use all 3 standards – 4, 7 and 10 and select “3-point calibration”. Follow the same steps as below.)
- It will indicate Buffer “1 of 2”
- Start with the lowest pH standard (usually pH 7) and rinse probe with standard three times
- Add standard to the fill line and select “Start”, it should detect the buffer value
- When stable, record the pre-calibration reading on the calibration sheet (it may take a couple of minutes to stabilize)
- Select “Accept” and record the standard value (i.e. 7.00) as the post calibration reading.
- It will immediately proceed to Buffer 2
- Rinse cup and probes with DI Water and add next buffer
- Repeat steps above with pH 7 or pH 10 for 2-point
Rinse probe with DI water.
Calibrate dissolved oxygen (DO) by selecting RDO Calibration, 100% Calibration
- Add a saturated sponge in the cup and select “Start” at the bottom of the screen
- When it is finished it will read “stable” and have 3 green check marks
- Record the initial reading and temperature
- Select “Accept”
- Use arrow to go back to main calibration page
- Remove damp sponge and rinse cup with DI water
Depth Calibration is only necessary if it is not reading zero out of the water
- Select Depth, Zero in Air
- Make sure the pressure sensor is open to the air
- When stable, select “Accept”
Final Meter Check:
After calibration is complete, a “check” is done to ensure proper calibration.
- Go back out of the calibration mode and to the Reading screen.
- Place the probe in the calibration cup with saturated sponge to get a DO reading. Record the DO reading.
- Rinse probe with conductivity standard and add conductivity solution to the calibration cup and place probe in the solution. Record the reading; it should be ±5% of expected value. Rinse with DI water.
- Rinse cup and probe with buffer solution and add pH buffer to the calibration cup and place the probe in the solution. Record the reading; it should be ±5% of expected value.
- Rinse off the probe and cup and prepare for the field.
- Connect multiprobe to the battery pack and turn on the battery pack and handheld device (e.g. iPad).
- Open the iSitu app on the handheld.
- Select your site from the list.
- If you are at a new site, you may need to create a new site at the bottom right. You will be able to add the Site Name, Description, take a picture and use the GPS or manually enter the Lat/Long coordinates.
- Select “save” and it will bring you back to the Site list. To take a reading, select “set” which will bring up the readings.
- Position the sonde in the thalweg (main stream flow); or along a bank/edge in the flow if the waterbody is too deep or fast; or lower from a bridge. Ensure the sonde is upstream of other sampling activity, in well mixed water and avoid disturbing bottom sediments.
- Wait 1-2 minutes for the values to settle and record them on the data sheet provided. Also select “record” which will save the values on the handheld.
When finished sampling, make sure the probe is properly stored in the cap with a damp sponge.