1. Product Overview
The Gain Express PHM-245 is a versatile 2-in-1 pH and Temperature Monitor designed for accurate measurement of water quality in various applications. This device provides simultaneous readings of pH levels and temperature, making it an essential tool for maintaining optimal conditions in aquariums, hydroponic systems, pools, and laboratory settings.
Image 1.1: The Gain Express PHM-245 monitor with its pH electrode, temperature probe, and product packaging.
Key Features:
- Accurate pH and Temperature Measurement: Monitors pH levels and temperature with high precision using separated electrodes.
- Automatic Temperature Compensation (ATC): Automatically adjusts pH readings for temperature variations between 0 to 50 °C (32 to 122 °F).
- Convenient Dual Display: Features a clear, backlit display showing both pH and temperature readings simultaneously, suitable for various lighting conditions.
- Easy Calibration and Replaceable pH Electrode: Supports 1-point manual calibration for accuracy and includes a BNC type replaceable pH electrode with a protective cap for easy maintenance.
- Comprehensive Kit: Comes with pH 4.01, 6.86, and 9.18 calibration powders for immediate use.
2. Components and Parts Identification
Familiarize yourself with the various parts of your PHM-245 monitor to ensure proper setup and operation.
Image 2.1: Labeled diagram of the PHM-245 monitor highlighting its display, buttons, and connection ports.
Included Components:
- PHM-245 Main Unit
- pH Electrode (BNC type) with protective cap
- Temperature Probe
- Power Adapter
- pH 4.01 Calibration Powder
- pH 6.86 Calibration Powder
- pH 9.18 Calibration Powder
- Mini Screwdriver for calibration
- Mounting accessories (suction cup, bracket)
- User Manual
Image 2.2: All items included in the PHM-245 product kit.
3. Setup Instructions
Follow these steps to set up your Gain Express PHM-245 monitor.
3.1. Unpacking and Inspection
- Carefully remove all components from the packaging.
- Inspect all parts for any signs of damage. If any damage is found, contact customer support.
- Ensure all listed components are present.
3.2. Connecting the Electrodes
- Connect the BNC connector of the pH electrode to the BNC socket on the bottom of the main unit. Ensure it is securely twisted into place.
- Connect the temperature probe to its designated port on the side of the main unit.
Image 3.1: Connecting the BNC type pH electrode to the monitor.
3.3. Powering the Device
The PHM-245 can be powered by either button batteries or a power adapter.
- Using Power Adapter: Insert the power adapter into the power adapter socket on the side of the unit, then plug it into a standard electrical outlet.
- Using Batteries: Open the battery compartment on the back of the unit and insert the required button batteries (typically 4x LR44, though the product description mentions 'Battery' as included component, it's often button cells for backup). Ensure correct polarity. Close the compartment securely.
Image 3.2: Battery compartment located on the back of the monitor.
3.4. Initial Placement
Place the pH electrode and temperature probe into the solution you wish to monitor. Ensure the electrode tip is fully submerged. The main unit can be mounted using the provided bracket and suction cup, or placed on a stable surface.
Image 3.3: The monitor in use, measuring pH and temperature in an aquarium.
4. Operating Instructions
4.1. Power On/Off
Press the ON/OFF button (power symbol) on the front panel to turn the device on or off.
4.2. Reading the Display
The monitor features a dual display showing both pH and temperature readings simultaneously. The pH value is displayed prominently at the top, and the temperature is shown below it.
Image 4.1: The clear dual display of the PHM-245 monitor.
4.3. Switching Temperature Units
Press the °C/°F button on the front panel to switch between Celsius and Fahrenheit temperature units.
Image 4.2: The button for switching between Celsius and Fahrenheit.
4.4. Calibration
Regular calibration ensures the accuracy of your pH readings. The PHM-245 uses a 1-point manual calibration method.
- Prepare Calibration Solutions: Dissolve the pH 6.86 buffer powder in 250ml of distilled water to create your primary calibration solution. You may also prepare pH 4.01 and pH 9.18 solutions for verification or if your application requires a different calibration point.
- Clean the Electrode: Rinse the pH electrode thoroughly with distilled water.
- Submerge Electrode: Place the pH electrode into the pH 6.86 calibration solution.
- Adjust pH: Wait for the reading to stabilize. Using the provided mini screwdriver, carefully turn the pH7 calibration trimmer until the display reads 6.86.
- Rinse and Test: Rinse the electrode again with distilled water. You can now test the accuracy by placing it in the pH 4.01 or pH 9.18 solutions to see if the readings are close to the expected values.
Image 4.3: Adjusting the pH7 calibration trimmer during the calibration process.
Image 4.4: pH buffer powders included for calibration.
5. Maintenance
Proper maintenance extends the life and accuracy of your PHM-245 monitor.
5.1. pH Electrode Care
- Always keep the pH electrode tip moist. When not in use, ensure the protective cap is filled with a storage solution (or pH 7 buffer solution) and placed over the electrode. Do not store in distilled water.
- Rinse the electrode with distilled water before and after each measurement.
- If the electrode becomes dirty, gently clean it with a soft brush and a mild cleaning solution, then rinse thoroughly.
- The pH electrode is replaceable. If readings become unstable or inaccurate even after calibration, consider replacing the electrode.
Image 5.1: The pH electrode with its protective cap.
5.2. General Cleaning
Wipe the main unit with a clean, damp cloth. Do not use abrasive cleaners or immerse the unit in water.
5.3. Battery Replacement
If using battery power and the display becomes dim or unresponsive, replace the button batteries in the compartment on the back of the unit. Ensure correct polarity when inserting new batteries.
6. Troubleshooting
This section addresses common issues you might encounter with your PHM-245 monitor.
| Problem | Possible Cause | Solution |
|---|---|---|
| Inaccurate pH readings | Electrode not calibrated; dirty electrode; expired calibration solution; damaged electrode. | Perform calibration (Section 4.4). Clean the electrode (Section 5.1). Use fresh calibration solutions. Replace the pH electrode if damaged. |
| No display or dim display | Low batteries; power adapter issue; unit off. | Replace batteries (Section 5.3) or ensure power adapter is securely connected and functional. Press the ON/OFF button. |
| Temperature reading incorrect | Temperature probe not fully submerged; damaged temperature probe. | Ensure the temperature probe is fully immersed in the solution. Contact customer support if the probe is suspected to be faulty. |
| pH reading fluctuates excessively | Unstable sample; air bubbles around electrode; electrode nearing end of life. | Ensure the sample is stable. Gently agitate the electrode to remove air bubbles. Recalibrate or replace the electrode. |
7. Specifications
| Parameter | Value |
|---|---|
| Model Number | PHM-245 |
| pH Measurement Range | 0.00 ~ 14.00 pH |
| Temperature Measurement Range | 0 ~ 50 °C (32 ~ 122 °F) |
| pH Resolution | 0.01 pH |
| Temperature Resolution | 0.1 °C |
| pH Accuracy | ±0.1 pH |
| Temperature Accuracy | ±1 °C |
| Automatic Temperature Compensation (ATC) | 0 ~ 50 °C (32 ~ 122 °F) |
| Display Type | LCD with Backlight |
| Power Source | Battery Powered (Button Cells) or Power Adapter |
| Product Dimensions | 2.17 x 0.01 x 0.01 inches (Main Unit) |
| Item Weight | 15.52 ounces |
| Manufacturer | Gain Express Holdings Ltd |
8. Warranty and Support
Gain Express provides a return policy of 30 days from the date of purchase. For specific warranty details or technical support, please contact Gain Express customer service. Refer to your purchase documentation for contact information.
Manufacturer: Gain Express Holdings Ltd
For additional information or to explore other products, visit the official Gain Express Store.
