We get it. Scientific testing can be confusing and maintaining instruments can sometimes feel complex. That’s why we’ve created this article to bring together the most common questions our customers ask, along with simple and clear answers. We hope this makes things easier for you, and if you need any further support, our in-house technical team is here to help.

How often should I calibrate my pH meter?

Calibrating your pH meter regularly is important for keeping your readings accurate. How often you should calibrate depends on how precise you need the results to be, but daily calibration is best. When you calibrate, make sure to use at least two calibration points that cover the pH range you’ll be measuring.

Does my new pH meter come calibrated?

Yes. Our in-house technical team at Hanna Instruments Australia calibrates and quality checks every meter before it is sent out. However, before taking your first measurement, we recommend hydrating the electrode and performing a quick calibration using the provided buffer sachets. This ensures the best accuracy from the start.

Which solutions should I use to calibrate my pH meter?

The calibration solutions you need will depend on your meter, your application, and your internal procedures. We offer a wide range of buffer solutions to suit different testing needs and standards. You can browse our full selection on our calibration solutions page: https://hannainst.com.au/products/solutions-reagents/solutions/calibration-solutions/

How long will my pH buffer last once opened?

Once opened, pH 4 and pH 7 buffer solutions will typically remain stable for about 4 to 8 weeks. More basic buffers, such as pH 10, have a shorter lifespan and should be used within 1 to 2 weeks for best accuracy.

What should I store my pH electrode in?

Always store your pH electrode in a proper storage solution, such as HI70300L. This solution maintains the correct concentration of the reference electrolyte, which is essential for the electrode to produce a stable and accurate mV signal. Without proper storage, the electrode’s performance and lifespan can be affected.

Do I need to calibrate an ORP electrode?

No. Unlike pH electrodes, ORP electrodes do not require calibration.

Can the HI3131B measure pH?

No. The HI3131B is a refillable combination ORP electrode with a universal BNC connector and measures the oxidation-reduction potential (ORP) of a sample in mV. To measure pH, consider one of our Hanna pH probes, such as the HI1131B or HI1048B.

Can I use an EC probe to measure salinity in my food samples?

While an EC probe measures the total concentration of ions in a sample, it cannot distinguish between different types of ions. Food samples are complex and contain many ions that can affect the reading. For accurate salinity measurements in food, we recommend using a salt titration method.

My dissolved oxygen electrode is dry. What should I do?

Rehydrating a DO probe is quick and easy:

1. Remove the red and black plastic cap or the membrane assembly.
2. Soak the bottom 1 inch of the probe in electrolyte solution for 5 minutes.
3. Rinse the membrane with electrolyte and refill it with clean electrolyte.
4. Gently tap the sides of the membrane cap to remove any trapped air bubbles.
5. Adjust the O-ring inside the membrane cap, then screw the membrane assembly back on with the sensor facing down.

This will ensure your electrode is ready for accurate measurements.

My DO readings are not stable. What should I do?

Electrolytic or polarographic DO sensors need a “warm-up” or polarization period before use. This process removes any oxygen in the electrolyte and usually takes several minutes. During polarization, the probe operates at a fixed voltage to prepare it for accurate and stable measurements. Once properly polarized, the probe will provide consistent DO readings.

Can I use the HI96750 to test potassium levels in blood?

No. The HI96750 Potassium Portable Photometer is not designed for measuring potassium levels in blood.

Does the HI729 measure fluorosilicic acid?

No. The HI729 Low Range Fluoride Colorimeter – Checker® HC is designed for fluoride measurement only and does not measure fluorosilicic acid.

Can the HI3844 Hydrogen Peroxide Test Kit be used in salt water?

Yes. The HI3844 kit can be used to test hydrogen peroxide levels in saltwater samples.

Can the HI83730 measure peroxide value in essential oils?

Yes, this photometer can measure peroxide values in essential oils, provided the oils are not highly coloured.

What is safe minimum internal temperature for foods?

All foods must reach at-least a minimum internal temperature. Use a food thermometer before removing food from the heat source.

Safe Minimum Internal Temperatures for Foods

• Poultry (chicken, turkey, whole or ground) – 165°F (74°C)
• Ground meats (beef, pork, lamb, veal) – 160°F (71°C)
• Beef, pork, lamb, veal (steaks, roasts, chops) – 145°F (63°C) and allow to rest for at least 3 minutes
• Fish and seafood – 145°F (63°C)
• Eggs and egg dishes – 160°F (71°C)
• Leftovers and casseroles – 165°F (74°C)

Key Tips:

• Always use a food thermometer to check internal temperatures.
• Colour alone is not a reliable indicator; meat can be pink even when safely cooked.
• Let meats rest for the recommended time to ensure any harmful bacteria are destroyed.

Can I measure the Total Residual Oxidants in our reef tank?

For low concentrations, the HI761 Ultra Low Range Total Chlorine Checker is ideal, delivering accurate readings down to 0.05 ppm.

When should I replace my electrode?

The lifespan of an electrode depends on its type, but here are general guidelines:

What should I do if it looks like something is growing in my storage cap?

Although our storage solution is stable, it’s possible to see some debris or growth in the cap – especially if it has been stored in a warm or humid area. This could be fungus or other buildup.

The good news: you can clean it! Wash the cap thoroughly, then rinse with DI water to remove any soap residue.

How do I dispose of the chemicals from a formol titration?

Proper chemical disposal is important; don’t just pour it down the drain!

Formol titrations use formaldehyde, which is classified as hazardous waste. Pouring it down the drain can damage pipes, cause chemical reactions, and may even result in fines from your local council or environmental authorities.

We recommend collecting the waste in a clearly labelled plastic jerrican. For detailed guidance, contact your local council or a licensed chemical disposal company. They can provide safe, compliant instructions for disposal in your area.

How much chlorine should be in my treated well water?

Treated drinking water should contain around 1 ppm of free chlorine.