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SOP — Hanna HALO2 pH Meter Maintenance

FUERST WIACEK Version 1.1 | Lab — Hanna Instruments HALO2 (HI9810422) | Frequency: store after each use; calibrate weekly

Purpose

This SOP covers cleaning, calibration, storage, and maintenance of the Hanna HALO2 wireless pH tester used for daily fermentation monitoring. For in-session use, refer to the Fermentation Monitoring SOP.

Equipment

  • Hanna HALO2 pH tester
  • Distilled water
  • Paper towels
  • pH 4.01 buffer sachet (Hanna)
  • pH 7.01 buffer sachet (Hanna)
  • Electrode cleaning solution sachet (Hanna)
  • Electrode storage solution (dropper bottle)

Storage — After Every Use

  1. Rinse the probe with distilled water. Wipe dry with a paper towel.
  2. Place the probe tip into the small pitcher containing storage solution.

Note

Storage solution in the pitcher is changed weekly.

Warning

Never store the probe in distilled or deionised water — this damages the electrode. Always use the dedicated storage solution.

Cleaning

If the probe is slow to respond, readings are sluggish, or measurements appear off:

  1. Soak the probe in electrode cleaning solution for 20 minutes.
  2. Rinse with distilled water.
  3. Soak the probe in storage solution for at least 30 minutes before calibrating or using.

Calibration

Calibrate using pH 4.01 and 7.01 Hanna buffer sachets. Use fresh sachets — once opened, buffer values can drift.

When to Calibrate

  • Before first use of the day when accuracy is critical
  • If readings appear inconsistent or implausible
  • After cleaning the electrode
  • After the probe has been replaced

Procedure — Stand-Alone (up to 3-point)

Calibration is a single continuous process — do not turn the meter off between buffers. The auto-off timer keeps running, so the rinse between steps must be quick.

  1. Prepare both buffer sachets (pH 7.01 and pH 4.01) and distilled water before starting.
  2. Rinse the probe with distilled water and wipe dry.
  3. Turn the tester on.
  4. Dip the probe into the pH 7.01 buffer sachet. Wait for the reading to stabilise — the stability indicator will show when ready. The tester automatically recognises the buffer and saves the value. It will then prompt for the next buffer.
  5. Quickly rinse the probe with distilled water and wipe dry.
  6. Dip into the pH 4.01 buffer sachet. Wait for stabilisation. The tester automatically recognises and saves the value.
  7. The tester returns to measurement mode. Calibration is complete.

Warning

Do not turn the meter off between step 4 and step 6. This resets the calibration state and you must start again.

Note

Always use fresh buffer from an unopened or recently opened sachet. Do not reuse buffer between sessions.

Maintenance Schedule

Task Frequency Notes
Storage (cleaning solution in cap) After every use See storage procedure above
Calibration Before use when accuracy matters; after cleaning 2-point: pH 4.01 and 7.01
Full electrode clean (cleaning solution soak) When probe is sluggish or readings drift 20 min soak, then rehydrate 30 min
Battery check As needed CR2032 — replace when battery icon is low
Buffer stock check Monthly Keep pH 4.01 and 7.01 sachets in stock

Maintenance Log

Date Task Result / Notes Initials
Calibration
Calibration
Calibration
Calibration
Calibration

Troubleshooting

Issue Likely Cause Action
Reading slow to stabilise Probe needs cleaning or rehydration Soak in cleaning solution 20 min, then storage solution 30 min
Reading implausible or drifting Calibration drift or contamination Recalibrate with fresh buffer sachets
Calibration fails Old or contaminated buffer Use a fresh sachet. Rinse and dry probe before dipping.
Probe dry or stored in water Improper storage Rehydrate in storage solution for 30 min before use
Battery low Normal wear Replace CR2032 battery. Reset date and time after replacement.