How to Test Aquarium Water

When starting a new aquarium you should test the water every four to five days. Test an established tank at least monthly, but more frequently is recommended for some tests. Monitor your aquarium water temperature, ammonia, pH, salinity, chlorine, hardness and oxygen level. Acceptable levels may vary depending on whether you have a fish-only or reef tank. Keep your fish healthy and alive by testing your aquarium water. Read on to learn how to test aquarium water.

Instructions

    • 1

      Maintain a saltwater temperature of 75 to 80 degrees F. A higher temperature creates excess algae. Measure temperature with a thermometer placed away from heating or cooling devices that could yield an inaccurate reading.

    • 2

      Check ammonia levels routinely. The build up of fish waste, decaying food and dead fish causes ammonia. An established tank should have a measurement of zero. See related eHow article titled "How to Test Aquarium Water Ammonia."

    • 3

      Prevent fluctuations in pH by more than 0.2 in a 24-hour period. The pH level is usually consistent with the tap water you put in your tank. An acceptable range is 6.5 to 8.0. The correct pH level is important to the growth of corals and biological processes.

    • 4

      Use a test kit to check the water hardness, which measures calcium and magnesium concentrations. This is particularly important in a reef tank because corals and invertebrates need calcium to grow their skeletons and shells. Most tanks do well with a harness level of 50 to 150 ppm (parts per million).

    • 5

      Measure dissolved oxygen with a test kit or electronic probe. Keep the dissolved oxygen in the range of seven to 10. Proper water and air circulation maintain a healthy oxygen level.

    • 6

      Test chlorine levels before you add fish to a new tank and when you do partial water changes. Use a test kit to check and treat tap water for chlorine before you add it to your tank. Then test and retreat the water once it is added to the tank.

    • 7

      Use a hydrometer to measure the density of the water for saltwater aquariums only. Strive for a constant salinity. Reef tanks should fall in the 1.023 to 1.025 range and fish-only tanks can be a bit lower at 1.020 to 1.022. Salinity increases as the water evaporates. Adding fresh water brings the salinity back up to the target range.