How to Test a Saltwater Reef Aquarium

Keeping a reef tank healthy requires constant monitoring and maintenance. There are a lot of different parameters that have to be checked including salinity, pH, hardness, ammonia, nitrogen, nitrites, nitrates and phosphorous. Most parameters are best monitored with chemical kits. Even though pH can be monitored using pH paper, a chemical kit is more accurate because pH paper can go bad over time once exposed to air. Each kit has specific instructions, but this will walk you through a general guide.

Things You'll Need

  • Marine testing kit
  • Watch
  • Hygrometer
  • Thermometer
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Instructions

    • 1

      Fill clean vials from the testing kit with water directly from your aquarium and then empty them. Dip the vials in the aquarium again and fill them to the fill line.

    • 2

      Locate the key card for the test you wish to run. Key cards have a color comparison chart on one side and list the reagents and steps for the particular test on the reverse side. Review the key steps before starting.

    • 3

      Identify the reagent to be used for the parameter you are testing. Some tests require two different reagents. Mix the reagents by inverting the bottle six times.

    • 4

      Clean the vial by rinsing with tap water and shake dry. Each test requires a clean vial. Kits often give you fewer vials than you will need to test all the parameters.

    • 5

      Place the lid on the vial and turn it upside down, or invert it, several times. Some tests require inverting for about 30 seconds. Time this using your watch. If a second reagent is required, add it and mix again.

    • 6

      Set the test vial down near the card and time the wait period indicated by your test kit instructions using the watch. Most tests require three to five minutes to reach full color.

    • 7

      Compare the color of the vial to the key card. If the color of the solution in the vial is between two colors on the card, average the two numbers.

    • 8

      Record the number and compare it to the desired parameters for that water property. For a reef tank the following parameters are ideal: pH 8.1 to 8.3; alkalinity 125 to 200 parts per million (ppm); magnesium 1250 to 1350 ppm; phosphate less than 0.03 ppm, and calcium 380 to 450 ppm. The nitrogen cycle phases should be below the following levels: 0.1 ppm for ammonia and 0.2 for nitrite and nitrate.

    • 9

      Test other parameters as desired including silica, with a recommended level less than 2 ppm; strontium recommended between 5-15 ppm, boron levels below 10 ppm and iron should be undetectable.

    • 10

      Determine the temperature of the tank using the thermometer. The ideal temperature range is 76 to 83 degrees for a reef aquarium.

    • 11

      Measure the salinity in the reef tank using the hygrometer. Rinse the hygrometer with the tank water and then fill to the line. The salinity, or specific gravity, in the reef tank should be 1.026.

    • 12

      Rinse all vials using tap water and dry before storing.