Why DO Calibration Matters
Bad DO readings create bad process decisions.
If your meter is wrong:
- aeration adjustments may be wrong
- nitrification may suffer
- operators chase fake problems
Step 1: Inspect the Probe
Before calibration I check:
- membrane condition
- electrolyte
- cable condition
- cleanliness
Dirty probes cause inaccurate readings.
Step 2: Allow Temperature Stabilization
DO readings depend heavily on temperature.
I let the probe stabilize before calibrating.
Step 3: Calibrate According to Manufacturer Instructions
Most probes use:
- air calibration
- saturated water calibration
I follow plant SOPs carefully.
Step 4: Verify Accuracy
After calibration:
- compare readings
- test in known conditions
I never assume calibration worked perfectly.
Common Problems
- damaged membranes
- low electrolyte
- fouling
- poor storage practices
Final Thought
A clean, calibrated DO probe is one of the most important tools in biological treatment.