How to Test for Nitrates in an Aquarium

Aquariums with high levels of nitrates should have their water changed.

When you own an aquarium, it is important to perform regular tests of the water to determine if it is suitable to sustain plant and fish life. There are many different test kits available to help you determine the levels in your aquarium, including pH kits, salinity kits, ammonia kits and nitrate kits. Nitrates are created from nitrites during the water cycling process. Although they are not as dangerous as ammonia, nitrates can harm your fish when present in large amounts. Most nitrate kits come as a liquid drop kit that requires a sampling of water from the tank.

Things You'll Need

• Nitrate liquid test kit

Instructions

1. Fill the test tube with water from the aquarium. Make sure the test tube is filled to the line marked on the side.

2. Add nitrate testing solution as indicated by the test kit instructions.

3. Wait as the drops mix with the water from the tank. The water will change color, indicating the level of nitrates in your water.

4. Hold up the test kit's color card beside the water in the tube and determine which color best matches the color of the water. Each color indicates a different level of nitrates. Your test tube and color card should indicate a level of less than 20 parts per million. In a tropical fish tank, the ideal nitrate level is zero.

Tips & Warnings

• It can be expensive to purchase several different water testing kits. Purchase a master kit that contains all the supplies to check the basic chemical levels of your aquarium.

References

• Fishlore: Aquarium Water Test Kits