API pH test kits
From The Aquarium Wiki
API liquid pH test kit tests for the pH of a water sample (your fill water or your aquarium water) in the range of 6.0 to 7.6. The test kit includes a bottle of testing solution, a test tube, and instructions including a color comparison chart. A drip test such as this test is considered more accurate than test strips.
Testing
- Rinse the test tube a couple of times in the water to be tested to clear out any impurities and old water.
- Fill the tube up to the mark (5 ml) with sample water.
- Holding the pH test solution upside down, drip 5 drops into the tube.
- Place the cap on the tube and shake it several times. I shake for 30 seconds or so.
- Let the tube stand for 5 minutes to allow thorough chemical reaction to take place.
- Hold the tube next to the color chart so white area of the chart is behind the tube and it is adjacent to the colors on the chart.
- The color closest to the tested water indicates the pH of the sample.
- When the test is complete, discard the sample water and rinse the tube several times. I usually keep about 5 ml fresh water in it with the cap on during storage do prevent mineral buildup on the inside of the tube).
