Testing your tile
Using the strips to test the water leaving your tile
- Check the expiration date on the bottom of the Nitrite-N/Nitrate-N bottle. If expired, DO NOT USE.
- Rinse a clean cup three times with the water exiting the tile line.
- Dip the test strip into the water for one second and remove. DO NOT SHAKE excess water from the test strip.
- Hold the strip level, with pad side up, for 30 seconds.
- Compare the NITRITE (lower) test pad to the nitrite-nitrogen color chart on test strip bottle. The nitrite concentration is in mg/L or parts per million (ppm). Remove sunglasses before reading the strip. The pad will continue to change color, so make a determination immediately after 30 seconds. You are not likely to have NITRITE present unless a fresh source of human or animal waste is present.
- At 60 seconds (or 30 seconds after estimating nitrite concentration), compare the NITRATE (upper) test pad to the nitrate-nitrogen color chart on test strip bottle. The nitrate concentration is in mg/L or parts per million (ppm). Remove sunglasses before reading the strip. The pad will continue to change color, so make a determination immediately after 60 seconds.
- Dispose of test strip in a waste container, which can be emptied into your household trash. STORE VIALS AT ROOM TEMPERATURE (not in a vehicle).
- Don’t stop at your tile line, test your creek, pond, wetland or fill a bucket and test your rainwater! Test at different times of the year for more information.
Calculating nitrate lost through tile lines
First, measure your tile flow rate. To do this you’ll need:
- Place the 5 gallon bucket underneath the tile line.
- Use a stopwatch to measure how many seconds it takes to fill the bucket.
- Use the formula below to measure how much nitrate is being lost per day.
(nitrate concentration × 0.0000083454) × (5 gallons/seconds to fill bucket) × 86400 = pounds of nitrate lost per day
For example, if your tile’s nitrate concentration is 7 mg/L (or 7 ppm) and it takes 125 seconds to fill up a 5 gallon bucket. The formula would be:
(7 × 0.0000083454) × (5/125) × 86400 = 0.2 pounds of nitrate lost per day
You can also divide the pounds of nitrate lost per day by the number of acres drained. This will give you the pounds of nitrate lost per acre each day.