There was no charge from Hagen when they sent me the directions.
Here's a little help but you'll have to use you imagination some. The Hagen chart only has 5 different colors and 5 different ppm concentrations. The medium pink colors are very close together on the direction's color chart. The dark pink colors are very close as well. In other words, there's not much difference in the color from 10 to 20 ppm (medium pink). Also there's not very difference in the color from 50 to 110 ppm (dark pink). 5 ppm (pastel pink) is easy to determine. So, there's basically only 3 different ranges.
Pastel Pink: 5 ppm
Medium Pink: 10 to 20 ppm
Dark Pink: 50 to 110 ppm
The EI target range for nitrate is from 5 to 30 ppm. So, if your test solution is a pastel pink or a medium pink color, you're OK. If it's dark pink, well....
Here's the directions:
1) Take a sample of the water to be tested with the pipette. Use it to fill a clean test tube to the 5 mL line.
2) Add 5 drops of Reagent #1 and 5 drops of Reagent #2 to the test tube. Insert cap. Hold in place with finger and shake well to mix. Always use the cap. Avoid skin contact.
3) Shake the Reagent #3 bottle vigorously (5 sec.) and add 3 drops to the test tube. Insert cap. Hold in place with finger and shake well to mix.
4) Wait 5 minutes for the color to develope, shake again, and match the test color to the closest color on the chart.
Maybe this will get you a little idea about the NO3 concentration in your tank. I tried anyway.