YSI 5200 - Manual (Page 109)

YSI Incorporated 107 5200 Recirculating System Monitor
Section 11. Maintenance
It is important to remember that the quality of data obtained will be heavily dependent on three factors
directly related to the probe:
Ö Proper attention to detail of and general maintenance at the physical deployment site of your
probe.
Ö A well-defined quality assurance program that is carried out on a regular basis to assure that the
sensors are performing properly.
Ö Proper periodic calibration and maintenance of the specific sensors.
The following sections are designed to help you in these important areas by providing maintenance tips for
the overall probe deployment, help in implementing a quality assurance protocol, and suggested service
methods and intervals for the sensors.
11.1 Probe Maintenance at the Deployment Site
11.1.1 Algae and Debris
The problem most likely to be encountered with regard to the overall probe deployment is fouling from
algae (and occasionally other debris). Algae will inevitably collect on any object immersed in the sample
stream, and, unless periodically removed, can seal off the sensor compartment of the probe. Once algal
build-up occurs, it isolates the sensor environment from the sample stream. Thus, even though the sensors
themselves may be relatively free of fouling and performing correctly, the readings may be non-
representative with regard to the sample stream.
To avoid, or at least minimize, this problem, it is necessary to periodically remove the algae from the
probe. This may require the complete removal of the unit from the sample stream and “hands on” removal
of the fouling. Removal of the probe is easier if it has been installed using an optional probe mounting kit.
See Section 20 Accessories, for more information.
Minimizing the Effect of Algae and Debris
The collection of algae on your probe and the frequency of cleaning can be minimized by the overall
deployment configuration and the way in which the probe is mounted. As outlined in Section 3.2.1
Choosing a Probe Location, it is preferable to angle the probe with (rather than against) the current of the
stream. This configuration will maximize the chances that much of the algae will be swept free of the
probe rather than collecting.
Remember that no matter what precautions you take, debris will still collect on the probe and the fouling
will have to be removed by periodic cleaning. Cleaning will be easier if the method of mounting allows
for easy removal and replacement of the probe. A little extra time spent on implementing a good
mounting arrangement using the optional probe mounting kits will save a lot of time in subsequent
cleaning operations. See Section 20 Accessories for more information.
The frequency with which you will have to remove fouling from your probe varies with the water being
monitored and with the physical arrangement of the probe, but the need for cleaning can usually be
ascertained by visual inspection. You can do no harm by excess cleaning, so it is best to err on the side of
caution, removing and cleaning the probe if any significant fouling is even suspected.