YSI DO200 - Manual (Page 7)

Procedure
1. For the field probe, place 5-6 drops of clean water (tap, distilled, or deionized) into the
sponge inside the calibration bottle. Turn the bottle over and allow any excess water to drain
out of the bottle. The wet sponge creates a 100% water-saturated air environment for the
probe, which is ideal for calibration, transport, and storage of the Model DO200 probe. For
calibration, the probe remains in a water saturated air atmosphere and is not submersed.
For the lab probe, simply use the same bottle the probe is stored in with approximately 1
inch of water in the bottom. This creates a 100% water-saturated air environment for the
probe, which is ideal for calibration and storage of the Model 200-BOD probe. For
calibration, the probe remains in a water saturated air atmosphere and is not submersed.
2. For the field probe, slide it into the calibration bottle. Be sure the membrane does not touch
the sponge.
3. Turn on the DO200 by pressing . Wait 10 to 15 minutes for the dissolved oxygen and
temperature readings to stabilize.
4. Press CAL.
5. The LCD prompts for the local pressure in mBar. Use the
Δ and ∇ keys to increase or
decrease the pressure value respectively. See the section titled ‘Conversions’ to convert
barometric pressure units to mBars.
6. When the proper pressure displays, press once to view the calibration value in the lower
right of the display. Once the value in the main display stabilizes, press again to move to
the salinity compensation procedure.
7. The display prompts for the approximate salinity of the water to be analyzed. Use the
Δ and
∇ keys to increase or decrease the salinity compensation value to the value of your sample
(between 0 to 40 parts per thousand [ppt]). When the correct salinity displays, press
.
8. The unit holds calibration even if it is powered off. However, it is recommended to check
calibration with each use and recalibrate as necessary to prevent drift. Dissolved oxygen
readings are only as good as the calibration.
PROBE MAINTENANCE
To clean the probes, use the YSI Probe Reconditioning kit (part number 5238) for the field
probe. For the lab probe, use the sanding disc included in the 5908 membrane kit and follow the
cleaning instructions outlined in the 200-BOD probe manual in regards to sanding. In addition to
the Reconditioning Kit and sanding disc with your 5908 membrane kit, you may try a chemical
cleaning. To clean the electrodes chemically, perform an ammonium hydroxide soak.
1. Remove membrane cap and rinse the probe with clean water (tap, distilled, or deionized).
2. Turn unit off, or disconnect probe.
3. Obtain either:
• 14 % lab strength ammonium hydroxide and soak for 2-3 minutes
• 3% household cleaning strength ammonia and soak overnight (8-12 hours)
4. Rinse ammonium hydroxide/ammonia from probe.
5. Use sandpaper (400 grit wet/dry, supplied with 5238 kit and with the 5908 membrane kit) to
buff (wet sand) excess deposits from probe.
6. Install a new membrane cap.
Never use chemicals or abrasives not recommended by YSI.
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