Aquarium Water Testing & Tank Maintenance

A Note on Cycling

Every new aquarium must go through a "cycling" period before it is ready for a full load of fish. Cycling is the natural process during which beneficial nitrifying bacteria colonize on and activate your biological filtration. These bacteria are essential in breaking down harmful compounds and waste bi-products keeping your tank chemistry stable and ideal for maintaining fish, inverts and plants. We recommend that you do not add your primary aquarium livestock before your tank is completely cycled. Please check out our guide to the Nitrogen Cycle for additional details.

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.

Water Changes and Filter Maintenance

Regular tank maintenance will keep your livestock looking vibrant and lively, and keep your water chemistry levels within healthy ranges. We recommend that you change 10 to 20 percent of the aquarium water every 1 – 2 weeks. You may need to change more or less depending on water test results, how heavily the tank is stocked, and the needs of specific fish.

You'll also want to check your filter cartridges and chemical media to see if they need to be rinsed or replaced. You should never have to replace your biological media. A clean and properly cycled tank will keep your fish happy and healthy.

If you use a gravel siphon to remove the water from the tank, you can maximize waste removal by vacuuming the substrate to remove excess debris that settles there at the same time. Vacuum a different section of the substrate each time you do a water change to avoid removing too much beneficial bacteria.

Replace the water you remove with new water prepared as necessary. If you use water directly from the tap, you may need to add a dechlorinator or allow the water to sit for a day or two. Saltwater should be mixed in advance, 24hrs if possible, to make sure the salt is completely dissolved. Be sure the replacement water is close in temperature and chemistry before you add it to the tank to avoid shocking your stock.

Additives and Supplements

Your water test results may show that you need to adjust the chemistry with an additive or supplement to reach ideal parameters. Supplementing trace elements and buffering your pH or hardness are also important aspects of maintaining an ideal environment for your fish.

Additional Equipment

We recommend adding the following products to your aquarium maintenance kit. While not essential, these tools to help make everyday aquarium maintenance less of a chore:

- A net and/or specimen container – these tools allow you to safely catch, inspect and transport livestock as necessary.

- A gravel siphon is an efficient way to remove water from the tank and remove debris from the substrate. Some models come with a short length of tubing for water removal only, while some kits come with parts that adapt the hose for refill as well.

- Algae Magnets and Scrapers are great for daily glass clean-up. Some have magnetic pieces that allow you to clean the glass without getting wet.

- Acclimation kit and bucket - for safe and proper acclimation of new fish and inverts. A dedicated, clean 5-gallon bucket serves many purposes when you maintain any aquarium.

- Aqua gloves prevent cuts and scrapes in addition to keeping arms and sleeves dry.

Visit That Fish Blog for more information on The Importance of Water Changes in Aquarium Maintenance.