YSI ADV6600 - Manual (Page 193)

Appendix E. Chlorophyll Measurements
ADV6600
Y S I Environmental
Page 183
Note the significant improvement in the overall noise level of the readings after the screen
was installed on 4/2/99. However, there is no guarantee that this solution will completely
solve spiking problems caused by macro algal species. In some applications, it may be
necessary to clean the sonde and probes at a frequent interval to minimize the number of
erroneous readings.
Another factor that can contribute to repeated spikes in the user’s chlorophyll data is wiper
malfunction so that the wiper assembly parks over the probe optics. This problem is
usually due to the edges of the fluorescent wiper becoming coated with non-fluorescent
material such as sediment that, in turn, prevents the sonde software from detecting the
wiper movement. If the spikes are due to this factor, then the problem will be corrected by
manually cleaning the wiper edges so that the fluorescent surface is restored.
Do I have to worry about the effect of variable temperature on my field readings?
This factor is definitely a consideration depending on the level of reliability you require if
the water at your site is at a significantly different temperature from that of calibration.
YSI studies show that, while the optics and electronics of the sensor show very little
temperature effect, the fluorescence of phytoplankton samples does vary significantly with
temperature. Generally, the chlorophyll in biological samples shows increased
fluorescence at lower temperatures with a factor of 1-2 % per degree Celsius. In practice,
this means that if, for example, the calibration temperature is 25 C and the water