pH Meters

Keep Your Water Fresh, Plants Happy With A pH Meter

Whether you're purchasing a pH meter for your hydroponic system, fish tank, to test your drinking water, or for professional laboratory use, you'll find a full range of brands, sizes, and styles available on eBay. It's easy to choose your preferred option by using the filters, or you might just view the Best Selling options to see what other people have been buying lately. Before you buy keep in mind the following information:

What are pH Meters?

pH meters are electric devices that detect the activity of hydrogen ions in a solution – including acidity or alkalinity. Scientifically, these electrodes are used as probes that are dipped into the test solutions and kept there long enough for the hydrogen ions in the test solution. This will then equilibrate with the ions on the surface of the bulb on the glass electrode, allowing the pH of the solution to be measured. This equilibration ensures a consistent pH reading.

Simply, the pH of water indicates whether it is acidic or basic. The range is 0 to 14, with 7 representing neutrality. A pH less than 7 implies acidity, while a pH greater than 7 suggests basic.

Pure water, for example, is neither acidic or basic, and should have a pH of 7.0.

How to use pH meters?

If you’re using a meter for the first time, here are a few important steps to get started:

  1. Allow enough time for your pH meter to warm up before using it.
  2. Rinse your electrode with distilled water in an empty trash beaker to clean it.
  3. Prepare your buffers and only keep them in the beaker for two hours.
  4. Place your electrode in a buffer with a pH of 7 to calibrate it, then start reading.
  5. Set the pH level.
  6. Using distilled water, rinse your electrode with each solution you test to avoid mix-up.
  7. Start reading after placing your electrode in the proper buffer for your sample.
  8. Set the pH level for a second time.
  9. Using distilled water, rinse your electrode and dry it with a lint-free tissue.

Choosing a pH meter

When you’re buying online, there are a few things to consider.

First you want to ensure that the metre you purchase is accurate - with accuracy levels generally ranging from +0.1 pH to +0.001 ph. Next, ensure your pH meters are calibrated as this will get better results. This calibration happens with the assistance of a pH buffer, with the most common solutions being 4, 7, and 10 – which are usually colour coded in red, yellow, and blue. You want a meter that has at least a two-point calibration.

Read the description to find out what electrode is used to measure the concentration of hydrogen ions. The electrode is the part of the meter that you placed in this solution. Most are made from glass, though there are other options available as well. Some have no-clogging technology which could be useful if you are testing foods.

Remember that pH readings can also be impacted by the temperature, so you want to make sure the one you purchase has been tested and has automatic compensation. Finally, you may want a pH meter that is small and can fit in a pocket, or larger for laboratory use. You may also want to see if the model you like is waterproof. And of course, always check your budget.