Testing Your Aquarium’s Water
The most important element to keep in mind in regards to your fish's health is the water. If the water in your fish aquarium is too cold, too hot, too alkaline or acidic or out of whack in any way, your fish could get ill, or at worst, die. The best way to keep an eye on your water quality is to test the water on a regular schedule.
Begin by checking the temperature of the water. You can get a special thermometer at the fish store to keep in your tank so you can check it regularly. If the water is too hot or cold, your fish can become stressed and become vulnerable to contracting a disease. Fluctuations in temperature can also stress your fish. Keep your tank away from drafts from windows, heating vents and doors.
Eac species of fish have their own temperature at which they feel most comfortable. Be sure and find out what that temperature is for the fish you have. When you add new water during tank maintenance, keep the temperature as consistent as possible. Adding water that is too hot or cold may shock your fish, or in the worst situation, even kill them.
The acidity in your tank is measured by pH. You can get pH test kits for very little cost at the fish store. Keeping the pH at the right level is very important for your fish, so you should have a kit at home for frequent testing. Your tank's pH level is measured on a numbered scale: 7 is neutral, and anything below 7 is on the acidic side, while everything above the 7 is on the alkaline side. Most fish prefer water pH to be a 6 or 7. Anything that is added to your tank can change the pH level, so if you add plants, gravel or other decorations, be sure to check the pH.
You can also get test kits to check for ammonia levels. Ammonia is measured in parts per million. A healthy tank should register zero, as ammonia can prove fatal for the inhabitants of your tank. If you have a biological filter running, it can help prevent ammonia buildup. Regular maintenance and cleaning of your tank and filter can also help keep your ammonia levels low.
Other chemical levels that should hover around zero for your fish's health include nitrites and nitrates. Test kits are available at the fish store that you can use. They will measure the levels in parts per million or milligrams per liter. If you are running a biological filter and still have high levels, you should check your filter as it may not be working properly. Clean out your filter as soon as possible and retest your water to see if it is making a difference.
There are two more tests that you should run on your water. You'll want a general hardness test and a carbonate hardness test. These tests do not cost a lot and should be easy to find at your local fish store. Water hardness varies depending on where you live. Most fish prefer soft water, which measures between 50 to 200 parts per million. Hard water is not healthy for most fish. The carbon hardness test is important because high carbon levels can help stabilize your pH levels.