1. Introduction
The Testo 205 is a robust handheld pH and temperature measuring instrument designed for use in semi-solid media. It is particularly suitable for applications in food production, such as monitoring the quality and maturation of meat in butcher shops, slaughterhouses, and the meat-processing industry. This manual provides essential information for the proper setup, operation, and maintenance of your Testo 205 device.
Figure 1: The Testo 205 Handheld T-bar pH Meter, showing its display and controls.
2. Key Features
- Simultaneous measurement of pH value and temperature in semi-solid media.
- Integrated temperature sensor for automatic temperature compensation, ensuring accurate pH readings.
- Maintenance-free pH probe with gel electrolyte, designed to be leak-proof and resistant to dirt.
- Hole diaphragm on the pH probe for quick and reliable measurements.
- User-replaceable combined pH measuring tip and temperature probe.
- Two-line, illuminated LCD display showing both pH and temperature readings.
- Automatic final value recognition (auto-hold function) with an audible advisory tone when readings stabilize.
- Storage cap filled with gel electrolyte to maintain probe hydration and extend its lifespan.
- Includes a belt/wall bracket for secure storage.
- Supports one, two, or three-point calibration.
3. Setup and Initial Use
3.1. Battery Installation
The Testo 205 uses 4 x LR44 button cell batteries. To install or replace batteries:
- Locate the battery compartment cover on the back of the device.
- Open the cover using a suitable tool (e.g., a small screwdriver or coin).
- Insert the 4 LR44 button cell batteries, ensuring correct polarity.
- Close the battery compartment cover securely.
3.2. Preparing the pH Probe
Before first use, or after prolonged storage, ensure the pH probe is properly conditioned.
- Remove the storage cap from the pH probe. The cap contains gel electrolyte to keep the probe hydrated.
- Rinse the probe tip with distilled water.
- Proceed with calibration as described in Section 4.1.
4. Operating Instructions
4.1. Calibration
Regular calibration is crucial for accurate pH measurements. The Testo 205 supports one, two, or three-point calibration using buffer solutions.
- Press the ON/HOLD button to turn on the device.
- Press the CAL button to enter calibration mode.
- Immerse the pH probe into the first calibration buffer solution (e.g., pH 7.00). Ensure the probe tip is fully submerged.
- The device will automatically detect the buffer and begin calibration. Wait for the reading to stabilize and the device to confirm calibration (e.g., by displaying "CAL OK" or a stable value).
- Rinse the probe with distilled water.
- For two or three-point calibration, repeat steps 3-5 with additional buffer solutions (e.g., pH 4.01 and pH 10.01).
- Exit calibration mode by pressing the CAL button again or waiting for automatic exit.
Note: For economical use of calibration solution, Testo offers calibration dosing bottles with integrated dosing apertures.
4.2. Taking a Measurement
To measure pH and temperature in semi-solid media:
- Ensure the device is calibrated and the probe is clean.
- Press the ON/HOLD button to turn on the device.
- Carefully insert the pH probe into the semi-solid medium (e.g., meat). Ensure good contact and sufficient depth for accurate readings.
- The illuminated display will show both the pH value and temperature simultaneously.
- The automatic final value recognition (auto-hold) will capture the reading once it stabilizes. An advisory tone will sound to indicate stability.
- To manually hold a reading, press the ON/HOLD button during measurement. Press again to release.
- After measurement, rinse the probe thoroughly with distilled water.
Figure 2: The Testo 205 being used to measure the pH of a semi-solid food product, demonstrating its application.
4.3. Mode Button
The MODE button allows you to switch between different display modes or access additional functions, if available. Refer to the on-screen prompts for specific options.
5. Maintenance
5.1. Probe Cleaning and Storage
Proper cleaning and storage are essential for maintaining the accuracy and lifespan of the pH probe.
- After each use: Rinse the pH probe thoroughly with distilled water to remove any residue from the measured medium.
- For storage: Always place the storage cap, filled with gel electrolyte, back onto the pH probe. This prevents the probe from drying out and ensures its readiness for future measurements.
- Deep cleaning: If the probe becomes heavily soiled, consult specialized cleaning solutions for pH electrodes. Avoid abrasive materials.
5.2. Replacing the pH Probe
The combined pH measuring tip with temperature probe is user-replaceable. If the probe's performance degrades significantly despite proper cleaning and calibration, it may need replacement.
- Gently twist and pull the old probe assembly from the main unit.
- Align the new probe assembly with the connector on the main unit.
- Push and twist gently until the new probe is securely attached.
- After replacing the probe, perform a full calibration as described in Section 4.1.
5.3. Battery Replacement
When the battery indicator appears on the display, replace the batteries as described in Section 3.1.
6. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Inaccurate pH readings | Probe not calibrated; dirty probe; dried-out probe; expired buffer solutions; damaged probe. | Perform calibration (Section 4.1); clean probe (Section 5.1); rehydrate probe in storage solution; use fresh buffer solutions; replace probe (Section 5.2). |
| Slow response time | Dirty probe; dried-out probe; low battery. | Clean probe (Section 5.1); rehydrate probe; replace batteries (Section 3.1). |
| Device does not turn on | Dead batteries; incorrect battery installation. | Replace batteries (Section 3.1); check battery polarity. |
| Display shows "Err" or similar error message | Probe issue; internal fault. | Check probe connection; try cleaning/recalibrating; if problem persists, contact Testo support. |
7. Technical Specifications
| Parameter | Value |
|---|---|
| pH - Electrode | |
| Measuring Range | 0 to 14 pH |
| Accuracy | ±0.02 pH |
| Resolution | 0.01 pH |
| Temperature - NTC | |
| Measuring Range | 0 to +60 °C (Short-term to +80 °C max. 5 min) |
| Accuracy | ±0.4 °C |
| Resolution | 0.1 °C |
| General Technical Data | |
| Storage Temperature | -20 to +70 °C |
| Operating Temperature | 0 to +50 °C |
| Weight | 135 g |
| Dimensions (L x W x H) | 145 x 38 x 167 mm |
| Battery Type | 4 x Button cell LR44 |
| Battery Life | 80 h (Auto Off 10 Min) |
| Display Type | LCD, 2 lines |
8. Warranty and Support
8.1. Warranty Information
Testo products are manufactured to high-quality standards. For specific warranty terms and conditions, please refer to the warranty card included with your product or visit the official Testo website. Keep your proof of purchase for warranty claims.
8.2. Customer Support
If you encounter any issues not covered in this manual or require further assistance, please contact Testo customer support. Contact details can typically be found on the Testo website or in the product packaging.
For more information, visit the Testo Store on Amazon.
