YSI ADV6600 - Manual (Page 69)

Section 4. Calibration and Diagnostics
ADV6600
Y S I
Environmental
Page 59
4-6.10. Turbidity
Before calibrating your 6026 or 6136 turbidity sensor, pay particular attention to the following
cautions:
• To properly calibrate YSI turbidity sensors, you MUST use standards that have been prepared
according to the procedures and guidelines listed in Standard Methods for the Treatment of
Water and Wastewater (Section 2130 B). Acceptable standards include:
• Formazin prepared according to Standard Methods guidelines.
• Dilutions of 4000 NTU Formazin concentrate purchased from Hach.
• Hach brand StablCal™ standards in various NTU denominations.
• AMCO-AEPA standards prepared specifically for the YSI turbidity probe and
purchased only from YSI.
Warning! Standards purchased from other vendors, including AMCO-AEPA standards
from suppliers other than YSI, are not approved for use with the YSI turbidity probe and
their use will likely result in both calibration errors and incorrect field readings.
• For AMCO-AEPA standards, the value entered by the user during the calibration protocol is
DIFFERENT depending on which sensor (6026 or 6136) is being calibrated. This reflects the
empirically determined fact that 6026 and 6136 sensors that have been calibrated to the same
value in the primary standard formazin will have different responses in suspensions of the
AEPA-AMCO beads. This effect is likely due to the larger optical cell volume of the 6136.
For example, the label of the YSI 6073 turbidity standard bottle indicates that the value of the
standard is 100 NTU when used for calibration of the 6026 sensor, but 123 NTU when used
to calibrate the 6136. Note that the phenomenon of a sensor-specific formazin/AEPA-AMCO
ratio is well known for sensors other than the 6026 and 6136.
• For best results, use only freshly prepared or purchased turbidity standards. Degradation of
standards can occur on standing, particularly formazin prepared from dilution of concentrated
suspensions such as Hach 4000 NTU standard.
• For most applications, purified water of any kind (distilled, deionized or filtered) will be
acceptable for the 0 NTU standard. This water can be obtained from a laboratory or can be
purchased at a local supermarket. It is not recommend that you use tap water as the 0 NTU
standard. For maximum accuracy at very low NTU values (below the specification of the
instrument), you may want to purchase turbidity-free water from YSI or another vendor
• Be certain that the probe compartment of the sonde has been cleaned and is free of debris.
Solid particles from this source, particularly those carried over from past deployments, will