Test Method for pH

Any aquarium hobbyist will tell you that pH is one of the most vital aspects of healthy aquarium water. Water's pH is essentially a measure of either its alkalinity or acidity on a zero to 14 scale, with 7.0 being neutral and anything above it being alkaline, while anything below it is acidic. Most freshwater fish require a pH of around 7.0, while saltwater fish require levels around 8.0-8.4. There are several methods that are used to measure the alkalinity of aquarium water, from basic litmus strips to more accurate electronic devices.

  1. Test Strips

    • Litmus test strips are by far the simplest way to measure pH. Most packages consist of several strips of paper that contain a chemical that reacts differently to different degrees of acidity or alkalinity. The pH is tested by simply dipping the strip in the water and noting the color change. Many strips, however, are not terribly accurate and only offer three degrees--acidic, neutral or alkaline--while very rarely telling you exactly where on the pH scale your water's pH lies. These are excellent for quick spot checks, but not accurate enough for serious measurement.

    Test Solutions

    • Another popular and far more accurate way to test pH is to use a pH testing solution. These are usually sold in kits composed of a test tube, a bottle of the solution and a color chart. Water from the tank is placed in the test tube, along with the indicated amount of solution (typically these solutions require three drops). The water will then change color, usually a shade of yellow, green or blue. The tube's color can then easily be compared with the color chart, which will indicate the level of the water's pH.

    pH Meters

    • Electronic pH meters are the most accurate way of testing pH, but are also the most expensive. The device looks similar to a calculator, with two wires attached to probes that are placed in the water. A gentle electric current is sent between them, and the water's pH is then recorded and displayed on the meter's LCD screen. These devices have become more popular with aquarium hobbyists recently thanks in part to their ease of use, accurate measurements and steadily declining prices, as they can be purchased from reputable online dealers typically for under $50 USD, which is still expensive compared with the other two methods, but the results may be well worth it.