PH meters

An electronic device that gives you a numeric reading of pH-values, usually with a glass probe. Calibration and correct storage is essential.

Calibration

In order to give a correct reading, the pH-meter must be calibrated. Some meters are calibrated around a single point, while more accurate meters are calibrated between two points on the pH scale. The calibration solutions are usually pH 4, pH 7 and pH 10, but look at the manual for your pH meter to select the correct ones. Which ones you will use, depends on what range you plan to measure in.

For freshwater tanks, you normally want to measure an ideal pH between 6.8 and 7.6, and you could with benefit use pH 7 and pH 10 calibration solution here, or just calibrate towards pH 7 alone.

For seawater tanks, you want to measure an ideal pH of 8.2. On a two point calibration, you will then use the pH 7 and pH 10 calibration solution.

With two points, you should get a more reliable reading from your pH meter, but one point may suffice depending on your needs.

Calibration solutions comes either as powders or as liquids. The pH 10 liquid is not very stable on the shelf. The powders however, have all good shelf life. You need RO/DI water to mix the powders into solutions you can measure.