A water test kit is a MUST for any serious aquarist because this will help to keep the pH-value under control. It is also important to test the water for ammonia, nitrites, nitrates and hardness. There are numerous test kits available and some more basic than others. Test kits capable of measuring the levels of ammonia, nitrate and nitrite and the pH-value will often be enough for the beginner aquarist.
A simple ammonia test kit is usually the first kit purchased by aquarists. This type of test kit will allow you to observe the progress of the nitrogen cycle even though it is only measuring ammonia, not nitrate and nitrite. The break in period, when the fish have been just introduced into the aquarium, is the most dangerous period. At this time, the beneficial bacteria that help in detoxifying natural wastes have not yet fully developed. Biological filters can also stop working later due to many reasons and this will typically cause a peak in the ammonia levels. A peak in the ammonia levels can for instance be caused by a dirty filter filled with debris, having too small a filter for the load of fish in your aquarium, or adding medicines that kills the beneficial bacteria.
The nitrite test kit is used for the same purpose as the ammonia test kit in its initial phase - testing the nitrogen cycle. This kit is not as essential to the beginner aquarist as the ammonia test kit. It will however make it easier for you to know what�s going on in your aquarium, and investing in a nitrite test kit can actually save you a lot of money since you will be able to rescue your fish before they all die from nitrite poisoning.
The nitrate test kit is more important than the nitrite test kit, and should ideally be purchased together with the ammonia before you set up your aquarium. At the end of the nitrogen cycle, nitrate levels peak since nitrate is the end product. Increased levels of nitrate are dangerous for the fish and even established aquariums can have high levels of nitrates.
Common indicators of to high nitrate levels are an oily shimmer at the surface of the aquarium and fish chipping for air on the surface. If the nitrate levels are too high, you should immediately do one or several water changes. Increasing the aeration of the water is also beneficial. If the problem persists, you must naturally try to determine the cause behind the high levels of nitrate.
The next important kit is the pH test kit. Before you buy fish, you will need to check out the pH of your water. The kind of fish you buy will depend on the pH of the water. Before they reach you, the fish may have been living in water that has a different pH than the pH in your aquarium and you will have to let such fish get time to adapt to the new values. Awareness of this will be helpful when you bring the fish home.
Many freshwater aquarium fish species have special requirements when it comes to pH-values and may not be able to thrive in your tap water even if you give them time to adjust to the new pH-value. You must either change the pH-value in the aquarium to suit the fish or choose fish species that will appreciate the natural pH-value of your tap water.
Most aquarium water test kits are very easy to use. They base their results on color changes in the sample of water being tested. Certain additives help to counter specific problems. Frequently, a water change is the most effective way to change the undesirable results in a water test.