14
Water Action Volunteers – Level 2 Manual
Updated January 2016
YSI 550a DO Meter Monitoring Procedure
Before going out to your stream site to monitor dissolved oxygen (or any parameter), please
remember to fill out the top portion of the monitoring datasheet with
your name (s)
, the
station name
, and the
station ID #
, as well as the
date and time of the monitoring event
.
It is also important that you indicate what type of equipment was used to monitor for dissolved
oxygen. In this case, you will circle the
YSI 550A Meter
option on your datasheet.
To measure dissolved oxygen (DO) in the stream:
1. With the DO meter in hand, enter the stream downstream from your monitoring
location (as to not disturb the bottom sediment as you move towards the site).
a. You can also monitor dissolved oxygen from a bridge overpass as to not disturb
the bottom sediment.
2. Remove the probe from its chamber and insert it into the water to be measured.
a. Continuously stir or move the probe through the water (especially when
monitoring in very still water) while taking the measurement.
3. Allow the temperature and dissolved oxygen readings to stabilize.
a. This should take anywhere from 2 to 5 minutes.
4. Observe and record the
water temp
and the
DO values
on the monitoring datasheet.
5. Press the MODE button to change the instrument display.
6. Observe and record the
% saturation value
on the monitoring datasheet.
7. Rinse the probe with distilled water after each use, and return it to the storage
chamber.
8. Before storing the meter in the carrying case, moisten the probe sponge by soaking with
distilled water.
9. Press the green button on the meter to turn if off at the conclusion of the day’s
monitoring effort.
