Sonde Notes Calibration

Chlorophyll Add 0.2 mL of acridine orange solution to 1000 total mL solution. In the LabView window, select "Calibrate", "Optic T-Chlorophyll", "Chl ug/L", "2 point". The first calibration point is pure water, enter "0" for ug/L. The sonde will calibrate and once the data settles around a point hit enter and accept the data. The second calibration point is the diluted acridine orange solution, the ug/L value can be obtained from the YSI manual (page 192) depending on temperature. The sonde will calibrate again and wait for it to find equilibrium around a point. Acceptable values can range around +/- 1. (We recommend running the pure water and acridine orange solutions again as samples to check that the calibration is correct.) If acridine orange solution is not available or is unusable, it can be made using 100 mg of acridine orange powder into 1 L of total solution.

Dissolved Oxygen Calibrate the DO probe in pure water. In the LabView window, select "Calibrate", "Dissolved Oxy", "DO mg/L". Enter "100" as the mg/L value. Allow the sonde to calibrate. Test the calibration by running a zero oxygen solution as a sample. To make a zero oxygen solution, dissolve 10 g sodium sulfite into 300 mL of pure water. Add "a shake" of cobalt chloride, which acts as a catalyst. Be sure to make the solution in a glass bottle. pH Calibrate the pH probe in buffered solutions. In the LabView window, select "Calibrate", "ISE1 pH", and "2 point". Use buffers of pH 4 and 7 to calibrate the sonde. Allow the probe to sit in the buffered solution for at least 60 seconds, enter the pH of the buffer and allow it to calibrate. Stop the calibration when it has settled at a value and then enter the pH of the second buffer. Run a sample of pure water to check the calibration. Oxidation Reduction Potential (ORP) Although it is not possible to calibrate the ORP, the values the sonde produces can be checked using Zobell solution. Zobell solution consists of 7.4555 g potassium chloride, 1.4080 g potassium ferrocyanide trihydrate, and 1.0975 g potassium ferricyanide. Run the solution as a sample to check the values against those on the chart on page 173. Depth In the LabView window, select "Calibrate", "Pressure-Abs", and enter the current depth of the Sonde. It is only necessary to do one calibration at a depth of one or two meters.

Operation

Daily Use Calibrate the pH, dissolved oxygen, and depth each day before using the Sonde. Store the Sonde with a small amount of water in the cover to keep it moist.

Running a sample Before using the Sonde each day calibrate the pH and DO. Allow time for it to warm up before taking a sample. We have found that filling the cover with a small amount of water and placing it over the sensor for about 30 minutes (with software hooked up and running) is generally necessary to eliminate errors in dissolved oxygen readings Open LabView and select YSI Control. Set up the battery and Bluetooth device by plugging the round Sonde cord into the battery box and plugging the box into an outlet. It will be necessary to run the generator. Under the first tab, Com6 should be selected for the Sonde and Com7 should be selected for the GPS. Wait until the status light on the Bluetooth device turns solid green and the status boxes for both devices show green check marks. Click the Run button (forward arrow). Go to the Terminal tab and double check that the correct Com is selected for the Sonde. Click the "Press to Activate Term" button and hit enter to show the main program menu. Toggle through the menu and run a discrete sample. Once the Sonde is ready and at the surface of the water, start the sample. Go to the "Set Up and Run" tab and press "open data log". Select the appropriate file you wish to log to. Select the "Acquire Data and Plot" button. Now the data is being collected and saved in the file. (During sampling, be careful to lower the Sonde slowly so that it is taking proper measurements. Also, use the Depth Window to watch the depth of the Sonde and make sure that it doesn't touch the bottom of the lake.) Each reading will gradually populate the data chart in the "Data Window". Data plots as a function of depth can be viewed dynamically in the "Depth Window" tab. When finished with the data, click the "Save Data to File" button and then click the "Stop Acquire" button. The data is now saved in the designated file and a new sample can be taken. Take note that the data will be lost if a destination folder has not been specified (see previous step). To run the next sample, return to the "Terminal" tab. Enter "0" in the command box to stop readings and bring up the main menu.