The Water Digital pH Meter
Measuring your water pH
One of the most important things you will frequently need to do is to measure your water’s pH.
When buying fish or invertebrates like shrimps and snails, or when checking why algae are appearing in your tank, or only checking if your aquarium water parameters are at the right level (read more about water parameters here).
There are mainly three ways to measure your water’s pH:
- Using Water Test Strips
- Using Chemical Reagents
- Using an Aquarium Digital pH Meter
In this article, I will discuss how to take care of your aquarium pH Meter Digital adequately. They are a sensitive equipment, and they need to be treated correctly to get excellent and precise measurements.
I will recommend a cheap but very efficient aquarium pH meter. Stay with me.
Carefully follow the instructions provided by the manufacturer.
Are Digital PH Meters good enough to be used with a freshwater aquarium?
Aquarium Digital PH Meters are very accurate and easy to use. They are an excellent choice to measure your aquarium water pH, but they are not easy to care for as they require frequent calibration and must be correctly stored and cleaned.
Lack of proper maintenance will cause wrong measurements.
Incorrect storage or incorrect handling of the electrode will cause wrong measurements as well.
My recommendation for a pH Meter Digital
The Digital pH meter I have been using and recommend is this one. It is a cheap pH meter that works just fine for what we want.
What is a Digital PH Meter midlife?
If not specified by your meter supplier, take one year as their mid-lie. You can see here how to know when you need to replace it.
How does a Digital pH Meter work?
For more information about how they work, follow these two links:
http://en.wikipedia.org/wiki/PH_electrode
http://en.wikipedia.org/wiki/Glass_electrode
http://en.wikipedia.org/wiki/Reference_electrode
I made this short video to show you how they work so you will have an idea about how to operate them.
Why is proper storage and conditioning necessary?
Your digital pH meter has a glass electrode with a fragile porous membrane that is exposed to the water and senses the concentration of H+ in the water. If the electrode is stored dry for some time, this membrane dries out, and a drop in conductivity inside the membrane occurs, leading to incorrect measurements.
For this reason, the membrane must be fully hydrated; otherwise, the measurement will be incorrect.
Can I store my digital pH meter dry?
When you buy your meter, it will usually come dry. You can store them dry too, but not for a long period.
If stored dry, they need to be conditioned before use. The membrane needs to be hydrated.
How to condition your Aquarium Digital pH Meter?
The easiest way to condition your meter is by submerging the electrode in tap water for about a day.
Do not use distilled, deionized, or RO water, which will damage your meter. When storing it in ion-free water, the ions will leave the glass to establish an ionic solution in the water itself, trying to achieve equilibrium (Law of Diffusion). This process where those ions from the glass move to the liquid, will damage your device and cause wrong measurements.
To properly store your aquarium digital pH meter, it is suggested that you use a pH-electrode storage solution. The storage solution is properly balanced with the right kind of ions. If you suddenly run out of storage solutions during a testing process, deionized water can be used in the very short term until more storage solutions can be obtained. Check your meter user documentation to get directions from the manufacturer.
Once the electrode is conditioned, it needs to be calibrated. Read more here.
How to store your digital pH meter in between measurements?
The electrode must be stored correctly between measurements to prevent the membrane from drying out again.
The best way to store your device is in a storage solution that will depend on what type of electrode you have and can usually be obtained from the manufacturer.
The alternative way (which can be used for shorter periods – a few days) is to store in tap (or tank) water. This will keep the membrane wet. However, it will slowly leach some of the components from the solutions inside the electrode, reducing the lifespan of your pH meter.
Before using it, briefly rinse it in distilled or deionized water.
To get truly accurate measurements, it is necessary to calibrate again if they have been stored in water for more than half a day or so.
Cleaning your Digital PH Meter?
After prolonged usage, your meter can accumulate some dirt, affecting the measurements’ accuracy. This can be taken care of with cleaning solutions available from the supplier or, alternatively, with dilute HCl (3.7% is common). Doing the occasional cleaning will again prolong the life of your pH meter.
How do I know when it is time to replace my digital pH meter?
One sign of the electrode coming to the end of its life is that it is further and further off when measuring the pH of the calibration between calibrations. Doing calibrations before each series of measurements will still give accurate readings for some time, but eventually, the electrode will give only erratic readings. Then it is time to get a new one.
How to properly clean my pH meter before and after I use it?
Before and after you use your meter, rinse it with some distilled or deionized water. Gently dry it out with a tissue, avoiding touching the internal parts of it.
Calibrating my Digital pH Meter
Different digital pH Meter brands have different calibration processes. Single-point measurement calibrations are good, but two-point or even three-point calibrations provide more accurate readings.
The video below shows how I calibrate my meter.
After calibrating again, rinse with some distilled or deionized water to remove any trace of calibration buffer, as this will affect the pH in your sample.
If you need extra bags of calibration solution, check this 15 pack.
Conclusion
Digital pH meters are a good choice for measuring your aquarium water pH.
A cheap pH meter like the one I am recommending can be replaced two or three times per year if needed.
They are very precise when correctly calibrated and maintained, but they require maintenance, as explained in this article. Lack of maintenance will make the device give you the wrong results.
If you don’t need a precise measurement, I strongly recommend you use Chemical Reagent pH test kits. They are easy to use, not expensive, and don’t need special care. For most cases, chemical reagent pH test kits are enough for your needs.
Start your journey using Chemical Reagent pH test kits and give you some time to feel the need for a digital meter.
References:
The BARR Report Website: “Effective use and care of pH meters and probes”
Iowa State University of Science and Technology – “pH Meter – Instrument” article
How to care for a pH Meter – Premier Scales & Systems
University of Massachusetts Amherst – “How to Use pH and EC “Pens” to Monitor Greenhouse Crop Nutrition”
Keep learning ! Check this article about Water Parameters
and learn about pH, Ammonia, Nitrite, Nitrate and much more.
