YSI ADV6600 - Manual (Page 116)

Section 9. Principles of Operation
ADV6600
Y S I
Environmental
Page 106
9-8. TDS
Procedure from Standard Methods for the Examination of Water and Wastewater: 2540
The electrical conductivity of environmental water is due to the presence of dissolved ionic species.
Thus, the magnitude of the conductivity (or specific conductance) value can be used as a rough
estimate of amount (in g/L) of these ionic compounds which are present. The ADV6600 software
provides a conversion from specific conductance to total dissolved solids (TDS) by the use of a
simple multiplier. The ADV6600 default value for conversion of specific conductance in mS/cm to
TDS in g/L is 0.65. However, this multiplier is highly dependent on the nature of the ionic species
present and should be determined for the water at the site where measurements will be taken.
9-8.1. Calculation of the TDS Constant
Use the following protocol to determine a TDS conversion factor:
1. Determine the specific conductance of a water sample from the site;
2. Filter a portion of water from the site;
3. Completely evaporate the water from a carefully measured volume of the filtered sample to
yield a dry solid;
4. Accurately weigh the remaining solid;
5. Divide the weight of the solid (in grams) by the volume of water used (in liters) to yield the
TDS value in g/L for this site; Divide the TDS value in g/L by the specific conductance of the
water in mS/cm to yield the conversion multiplier. Be certain to use the correct units.
The ADV6600 assigns a default conversion factor of 0.65 for TDS from specific conductance in the
sonde firmware. After you have determined your specific conversion constant as described above,
enter it by first accessing the Sonde Menu and then selecting Advanced|Sensor. Type the correct
number for the TDS Constant, change the value, and then press Enter to confirm the new value.
Remember that if you want TDS data to be stored during an ADV6600 sampling or monitoring
study, it MUST be active in the Report with the proper units selected.
9-9. Dissolved Oxygen
Procedure from Standard Methods for the Examination of Water and Wastewater: 4500-O G.
The ADV6600 employs the patented YSI Rapid Pulse system for the measurement of dissolved
oxygen (DO). Use of this technology provides major advantages for the monitoring of DO without
significantly compromising the accuracy of sampling applications. Standard electrochemical