A clear mountain stream might have a turbidity of around 1 NTU, whereas a large river like the Mississippi might have a dry-weather turbidity of around 10 NTUs. These values can jump into hundreds of NTU during runoff events. Therefore, the turbidity meter to be used should be reliable over the range in which you will be working. Many meters in this price range are designed for field or lab use. Although turbidity meters can be used in the field, volunteers might want to collect samples and take them to a central point for turbidity measurements.
Volunteers can also take turbidity samples to a lab for meter analysis at a reasonable cost.
TASK 2 Prepare before leaving for the sampling site Refer to section 2.3 - Safety Considerations for details on confirming sampling date and time, safety consideration, checking supplies, and checking weather and directions. TASK 4 Analyze the sample The following procedure applies to field or lab use of the turbidity meter. Prepare the turbidity meter for use according to the manufacturer's directions. Use the turbidity standards provided with the meter to calibrate it. Make sure it is reading accurately in the range in which you will be working.