Aquarium water test kits are an important item for hobbyists to keep on hand. The water you pour into the tank has several characteristics that you need to consider. These include the pH, how hard or soft it is, and any chemicals that may have been added that could endanger the fish.
In addition, the fish introduce other compounds into the water that will slowly reduce the water quality. Looking at the water tells you nothing about its chemistry and very little about its quality.
Monitoring water chemistry and water quality requires test kits. It is surprising how many people will spend a substantial amount of money for an aquarium setup but balk at spending a few extra dollars for three basic test kits -- ammonia, nitrite, and pH.
There are actually many more types of test kits available, but these three are the minimum needed to check the water. Other kits test for nitrate, copper, chlorine, dissolved oxygen, and more.
There are differences in test kits that you will want to take into consideration when choosing them. Some kits have liquid components, or reagents, that test the water, and others have dry reagents. As a rule, dry reagent kits have a longer shelf life and are more reliable than kits with liquid reagents.
However, all test kits have a limited shelf life, so you want to buy only kits that have expiration dates for the reagents clearly marked either on the box or somewhere on the packaging inside.
You will find that some kits are easier to use than others. In particular, be aware that most kits require you to compare the color of the water sample being tested with a set of standard colors in order to judge the results of the test.
Ideally, because you will be holding the vial with the test sample up to the light to see the color, the set of standard colors should be viewed the same way. Unfortunately, most test kits use a printed color chart, which forces you to compare a sample illuminated by direct light with a chart using reflected light, which can make accurate comparison difficult.
The ammonia and nitrite test kits are the most critical. The kits are used both to monitor the rise and fall of these compounds, indicating the completion of the initial nitrogen cycle, and as a regular check on the water quality.
If any of your fish become sick and upon checking the water you discover that either ammonia or nitrite is higher than it should be, you will have a clue as to the source of the problem.
Learn more about aquarium water pH levels on the next page.