Things You'll Need
- Nitrate liquid test kit
Instructions
Fill the test tube with water from the aquarium. Make sure the test tube is filled to the line marked on the side.
Add nitrate testing solution as indicated by the test kit instructions.
Wait as the drops mix with the water from the tank. The water will change color, indicating the level of nitrates in your water.
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.