Aquarium Water Testing & Tank Maintenance

Testing Your Water Chemistry

A biologically unstable aquarium can be harmful to your fish and plants. Keeping several basic test kits at home is highly recommended. Aquarists should monitor pH, ammonia, nitrite, and nitrate levels, on a regular basis (as well as salinity or specific gravity in a saltwater set-up). Kits to test other levels including phosphates, hardness, silicates, and a variety of trace elements are also available depending on the type of aquarium you have and issues that may arise.

Testing your aquarium on a weekly or bi-weekly schedule can help you stay ahead of chemistry issues before they affect the health of your stock. Newly set up aquariums can have particularly active chemistry until the cycle is complete. The type of tank you have and the species of fish you keep will dictate where your levels should be. Ammonia and nitrites are toxic and should be minimized or test at 0 ppm (these levels may spike at times, particularly if the tank is cycling).

pH levels can vary through the day. The best time to test pH is after your lights have been on for a few hours. Some fish prefer soft and slightly acidic water, while others need hard water and a more alkaline environment to be at their best. Generally for freshwater mixed communities we recommend pH be maintained between 6.8 and 7.2, and 8.0 to 8.4 in a saltwater aquarium. Ammonia and nitrite should always be at zero (except in a new tank). Nitrate levels of more than 40 ppm indicate that it is time for a partial water change. Certain species of fish, corals and invertebrates can be particularly sensitive to water quality and chemistry, make sure you know the requirements of the animals you are keeping, and test your water to stay within acceptable tolerances.

Home test kits and testing equipment are convenient and easy to use. You may choose test strips, drip/titration test kits or electronic probes and monitors. Test strips are dipped directly into the aquarium water and produce quick, relatively accurate readings of basic chemistry parameters. Drip/titration kits use a sample taken from the aquarium and deposited in a small vial. The reagents are applied to the sample in prescribed amounts resulting in a distinct color change. These kits produce highly accurate, easy-to-decipher readings. Electronic tools can be used on any aquarium set-up but are most often employed on reef aquariums and other complex set-ups. These monitors report highly precise digital readings using probes that are placed into the aquarium or sump. Some models even interface with home computers or mobile phones to report and store results and alert you if attention is required.