IOP 019A.1
Effective Date: 1/11/2017
Page 2 of 11
Dissolved oxygen
–
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Chlorine, sulfur dioxide, nitric oxide, and nitrous oxide can affect readings by behaving like
oxygen at the membrane.
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Static electricity may affect readings.
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Gold Cathode - The gold cathode on the sensor must be textured properly. It may become
tarnished or plated with silver after extended periods of use.
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Bubbles under the membrane cap will affect readings.
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Excessive water in calibration/storage sleeve will affect calibration.
pH
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Do not measure pH in metal containers.
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Water currents in streams can cause unstable readings.
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pH measurements will drift if the sample is not stirred.
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Do not expose the meter or probe to freezing temperatures.
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High humidity and cold temperatures may affect meter operation.
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Be sure that the temperature sensor is immersed in the sample.
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Buffers degrade from exposure to light - change daily
Ammonium
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Ammonium sensors should only be used at DEPTHS OF LESS THAN 55 FEET (17
METERS). Use of the sensors at greater depths is likely to permanently damage the sensor
membrane.
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Ammonium sensors should only be used in FRESHWATER.
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Temperature and pH sensors must be installed, calibrated and functioning correctly in order
for accurate ammonia values to be calculated from ammonium sensor measurements.
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Exposure to the high ionic content of pH buffers can cause a significant, but temporary, drift
in the ammonium sensors. Therefore, when calibrating the pH sensor, remove ammonium
sensor from the cable bulkhead and plug the port. After pH calibration is complete, replace
the ISE sensors and proceed with ammonium calibration. Alternatively, the ammonium
sensor may be covered with a tightly fitting rubber cap during pH calibration. Failure to
follow this protocol will result in ammonium calibration times of SEVERAL HOURS.
SAFETY
No special precautions
PROCEDURES:
I.
Configuration – The YSI Pro Plus instrument is capable of simultaneous measurement of multiple
water chemistry parameters including temperature, conductivity, pH, dissolved oxygen,
ammonium, chloride, and nitrate. This IOP is limited to the parameters typically measured by
the SLCP (temperature, pH, dissolved oxygen, and ammonia). Information on additional
capabilities of the Pro Plus instrument are available in the User Manual and Calibration Tips
documents available from YSI.
A.
Instrument overview
1.
Meter – The YSI Pro Plus handheld meter includes internal hardware and
software for calculation of parameters, a display screen, and a keypad for data
entry and screen navigation. The meter includes an internal barometer.
2.
Cable – The instrument cable connects the meter to the sensors. The SLCP uses
the quatro cable which has a four sensor capacity.
