OK, I am going to take a well water sample to my fisheries class tomorrow. We us Lammotte tests up there. I will check and see how much NO3 I have in my tap for sure. I will also bring my aquarium water. I am using Seachem Equilibrium as a GH booster for now, had no idea that it contained K. I will hold off dosing K2SO4 for potassium since I very well now see that I am getting plenty of K through my gh booster, KNO3 and KH2PO4. (This is right, right?) Thanks for all the help guys.
A good idea is to make the NO3 reference standard, your teacher should like this and be willing to help you make a standard calibration curve for the Lamotte test kit. I'd make a solution as follows:
Here's a way to make 10, 20, 30 and 40 ppm NO3 reference solutions:
Add 1.631 g of KNO3 to 1 L DI/RO water. This makes a 1000 ppm NO3 solution. (It's really a 1000.29 ppm solution.)
Add 2 mL of the 1000 ppm solution to 18 mL of DI/RO water. This makes 20 mL of a 100 ppm NO3 solution.
Add 15 mL of the 100 ppm solution to 15 mL of DI/RO water. This makes 30 mL of a 50 ppm NO3 solution.
To make a 10 ppm NO3 solution:
Add 2 mL of the 50 ppm solution to 8 mL of DI/RO water. This makes 10 mL of a 10 ppm NO3 solution.
To make a 20 ppm NO3 solution:
Add 4 mL of the 50 ppm solution to 6 mL of DI/RO water. This makes 10 mL of a 20 ppm NO3 solution.
To make a 30 ppm NO3 solution:
Add 6 mL of the 50 ppm solution to 4 mL of DI/RO water. This makes 10 mL of a 30 ppm NO3 solution.
To make a 40 ppm NO3 solution:
Add 8 mL of the 50 ppm solution to 2 mL of DI/RO water. This makes 10 mL of a 40 ppm NO3 solution.
There you go, now you can check to the test and you should plan on doing this for each parameter you measure in the course of your academic career.
Otherwise, you are simply guessing and assuming the test is correct, a 10-15$ cheapo API test kit is accurate without ever checking to see? I've calibrated several test from API, they read 40ppm of NO3 when it was pure RO/DI water. Some came close, others did not, most cheaper test kits where way off test kit to test kit. +/- 10-20ppm is not particularly accurate in the higher ranges either. Color charts are poor and you need a reference for that for your eyes alone. Even with a 10,000$ beckman analyzer or 50$ lamotte or a 15$ API test kit.
Would you use a pH meter without using the stand 4 and 7(or 10pH) references to calibrate it? Testing is more involved if you want to do it right and be sure. If not, then do not bother with testing and go water changes and observe the tank. 95% of this hobby is good low/moderate light and good CO2 management(if used). Nutrients are easy, but if you test, test the right way.
Then you know the results are good and you can now base a management plan/decision for dosing on the results. This is what the class would require if it was a lab exercise.
Regards,
Tom Barr
