A test of Nitrate Test Kits

Isn't the low levels the only important thing. Anything over 10 ppm and you can use a quick 5in1 test strip. In fact I find the test strip to be about as good as anything else for nitrate. I'm looking for no color change. If there is a hint of purple, I need to step up my nitrate control.
I agree, IMO the detection limit is more important than absolute accuracy at higher levels.
 
LOL, I have this very good alarm clock called Liida (a 2 year old girl) :D She seems to think it's important to go through 1000s of digital photos at 5:30 AM :rolleyes:
 
Thank you so much...For a new nano tank owner the water quality is so importand i have lost 2 clown fish becayse my water levels were off I bought salifert and i guess i can't read them correctly unfortunatly two fish gave their lives for my mistake i will have great water levels before i add two more. Thanks
 
NO3 and PO4 test are notorious for inaccuracies.

I did a similar test with some test kits about 13 years ago in SF for freshwater planted systems.

Lamotte was the suggested test kit back in 1996 as a result. SeaChem at least supplied a 10ppm reference to check, but color charts are tough.

Few aquarist bother to test correctly and yet want to make all their management decisions based on unverified data from these non calibrated test kits/methods.

Testing is a PITA, no doubt, getting the aquarist to test is tough, getting to test and calibrate is 10X harder.

So if you want to make some reference solutions, just like when you calibrate a pH meter with 2 reference standards(or would you just guess with a pH meter too?).

Rather than be a nag, I'd suggest folks make their own standards and then calibrations and verify their test kits/methods. This is done for 10,000$+ lab spects for research, I see no good reason not to do it for cheapo hobby test kits.

Here's how for cheap:


Directions for Making NO3 and PO4 Reference Solutions III


You will need the following:
- 1 liter of distilled water
- 500 mL graduated cylinder
- 50 mL graduated cylinder
- 1 mL or 3 mL pipette or another measuring device to measure small mLs of solutions
- Scales that are accurate to two decimal places
- KNO3 and KH2PO4 dry fertilizers


Here's a way to make 10, 20, 30, 40 and 50 ppm NO3 reference solutions:

Add 0.70 grams of KNO3 to 429 mL of distilled. This makes a 1000 ppm NO3 solution. (It's really a 1000.72 ppm NO3 solution.)

Add 2 mL of the 1000 ppm solution to 18 mL of distilled water. This makes 20 mL of a 100 ppm KNO3 solution.

Add 15 mL of the 100 ppm solution to 15 mL of distilled water. This makes 30 mL of a 50 ppm KNO3 solution.
* Note: You can use this for the 50 ppm NO3 reference solution.

To make a 10 ppm NO3 solution:
Add 2 mL of the 50 ppm solution to 8 mL of distilled 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 distilled 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 distilled 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 distilled water. This makes 10 mL of a 40 ppm NO3 solution.



Here's a way to make 0.1, 0.2, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 ppm PO4 reference solutions:

Add 0.70g of KH2PO4 to 489 mL of distilled water. This makes the 1000 ppm PO4 solution. (It's really a 999.04 ppm PO4 solution.)

Add 1 mL of the 1000 ppm solution to 9 mL of distilled water. This makes 10 mL of a 100 ppm PO4 solution.

Add 2 mL of the 100 ppm solution to 18 mL of distilled water. This makes 20 mL of a 10 ppm PO4 solution.

To make a 0.1 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 99 mL of distilled water. This makes 100 mL of a 0.1 ppm PO4 solution.

To make a 0.2 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 49 mL of distilled water. This makes 50 mL of a 0.2 ppm PO4 solution.

To make a 0.5 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 19 mL of distilled water. This makes 20 mL of a 0.5 ppm PO4 solution.

To make a 1.0 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 9 mL of distilled water. This makes 10 mL of a 1.0 ppm PO4 solution.

To make a 2.0 ppm PO4 solution:
Add 2 mL of the 10 ppm solution to 8 mL of distilled water. This makes 10 mL of a 2.0 ppm PO4 solution.

To make a 3.0 ppm PO4 solution:
Add 3 mL of the 10 ppm solution to 7 mL of distilled water. This makes 10 mL of a 3.0 ppm PO4 solution.

To make a 4.0 ppm PO4 solution:
Add 4 mL of the 10 ppm solution to 6 mL of distilled water. This makes 10 mL of a 4.0 ppm PO4 solution.

To make a 5.0 ppm PO4 solution:
Add 5 mL of the 10 ppm solution to 5 mL of distilled water. This makes 10 mL of a 5.0 ppm PO4 solution.

A cheap 0.01 gram scale is mighty cheap.
The KNO3 and KH2PO4 are also very cheap, see www.aquariumfertilizer.com.

Now you can check your test kit and then make a much better informed verified decision on management.

A trick to do also if you hate testing often, is to freeze small samples, say 50mls in a plastic bottle and label them with the date, then test all at once for 1 month's worth of measurements. This gives good data over time, but does not allow you to make changes day to day, or week to week, but longer term trends etc/good for testing certain hypothesis etc.

Do not take the word of this person's results and then skip this step!!!!Verify yourself for your test kit!!! Assuming their results are the same as your test kit is no good!!!! Calibration does not work that way. Each kit and hobbyists, over time, should do this if they want good results they can count on.

If you wanna guess, might not bother testing much.



Hope this helps

Regards,
Tom Barr
 
dont sell the seachem low range nitrate kit short it comes with a reference sample and is very cheap and easy to use.
MY NITRATES ARE IN THE .9 TO .5 RANGE AND THIS THING ROCKS IN THAT RANGE and for anything up to its reference sample level to 10 its the best.........period

YOU can get the samples they use for the nitrate meter to check your test if you dont use seachem.

Awt and seachem test were always the same have tested them together 10 times.
 
FWIW, AWT's testing is suspect. As is the Seachem nitrate kit from my testing.

The LaMotte appeared to perform the best for accuracy and ease of use.

I don't put much stock in reference samples supplied with hobby grade test kits. It is too easy to match the sample to the kit no matter what it is reading.
 
Next up, I may tackle testing an electronic nitrate monitor. Stay tuned.


Do you know which one you'll be testing?Was gonna order the hanna nitrate meter but heard it wasn't accurate.But I'll wait for your test.

Great job:thumbsup:
 
Some say shake and some say swirl gently. I generally do what the instructions call for. :)

I am not talking about the test tube.....what i mean is the dropper bottles...some test kits say to shake the bottle before adding the drops and others dont but i have always shook them anyway.
 
FWIW, AWT's testing is suspect. As is the Seachem nitrate kit from my testing.

The LaMotte appeared to perform the best for accuracy and ease of use.

I don't put much stock in reference samples supplied with hobby grade test kits. It is too easy to match the sample to the kit no matter what it is reading.

I do not either, however, I also use at least 2 standards over the suspected range of the test, Lamottes are the only test kit I have suggested for hobbyists for what? 14 years now for NO3.

That's why you folks should make your own reference samples and not rely on other folks for making and doing all the work, this(not calibrating the test kits/methods) is a much more larger problem in the hobby.

If you are honest and will not ever really make a standard reference solution, then get a Lamotte NO3 test kit.

If you are serious about testing, then do yourself a favor and use reference standards. There's no 1/2 half fudging on this, you either verify or you "guess". Once you do it a couple of times, it becomes "old hat", just like the first time you goaded yourself into actually testing NO3, seemed a bit new and intimidating.

You'll get over it and then know what the measurement is(or is not).

If you have a 0.001 accurate scale, then you get another sig figure, or you can make 1 liter of reference or 10 liters worth and sell it to local hobbyists and get another sig figure by using 10X(1 sig figure) or 100X more volume(2 sig figs), but what to do with 100 liters of 100ppm NO3 solution?:clown:

You can also do this without a scale using a dosing cal and teaspoon measurements: a non chemist method:


Calibrating a test kit means using that kit to measure some water samples with known concentrations of the substance being tested for, and using those test results to verify that the test kit is accurate, or to train yourself to recognize the colors that correspond to the concentrations you want to test for. Hobby test kits are not laboratory quality tests. That means we don't need extreme accuracy in the standard test solutions we use for calibration. If we have a good quality gram scale, with +/-.01 gram accuracy, and good laboratory glass graduated cylinders to measure water volume, there are other articles that tell how to make very accurate standard solutions. The methods described here are for use with ordinary kitchen measuring equipment, measuring spoons and cups. And, a simple dosing calculator was used to easily calculate how to mix these.

Nitrate Test Kits

First, buy a gallon of distilled water from your local grocery store. Use that to make the test standard solutions.

1. Add 1/4 teaspoon - a level measure, not a heaping measure - of KNO3 to 4 cups of distilled water (one quart). This gives you 4 cups of 800 ppm nitrate water.
2. Mix 1/4 cup of that 800 ppm water with 1 3/4 cups of distilled water. This gives you 2 cups of 100 ppm nitrate standard water.
3. Mix one cup of that 100 ppm water with one cup of distilled water. This gives you 2 cups of 50 ppm nitrate standard water.
4. Mix one cup of that 50 ppm water with one cup of distilled water. This gives you 2 cups of 25 ppm nitrate standard water.
5. Mix 1/2 cup of that 25 ppm water with 3/4 cup of distilled water. This gives you 1 1/4 cups of 10 ppm nitrate standard water.
6. Mix 1/4 cup of 25 ppm water with 1 cup of distilled water. This gives you 1 1/4 cups of 5 ppm nitrate standard water.
7. Use your test kit to measure the nitrate concentration in each of the 5,10,25, and 50 ppm nitrate standards. If you wish, add the 100 ppm standard to that set.
8. Compare the colors of those to the color card for your kit, and either verify the accuracy of the kit, or use those colors to train yourself to recognize the colors.

Your nitrate test kit is now calibrated. You can store the standard solutions in tightly sealed bottles for an indefinite period of time for future calibrations. Ideally, you calibrate the kit each time you use it.

Phosphate Test Kits

First, buy a gallon of distilled water from your local grocery store. Use that to make the test standard solutions.

1. Add 1/4 teaspoon - a level measure, not a heaping measure - of KH2PO4 to 4 cups of distilled water (one quart). This gives you 4 cups of 1000 ppm phosphate water.
2. Mix 1/4 cup of that 1000 ppm water with 2 1/4 cups of distilled water. This gives you 2 1/2 cups of 100 ppm phosphate standard water.
3. Mix one cup of that 100 ppm water with one cup of distilled water. This gives you 2 cups of 50 ppm phosphate standard water.
4. Mix one cup of that 50 ppm water with one cup of distilled water. This gives you 2 cups of 25 ppm phosphate standard water.
5. Mix 1/2 cup of that 25 ppm water with 3/4 cup of distilled water. This gives you 1 1/4 cups of 10 ppm phosphate standard water.
6. Mix 1/4 cup of 25 ppm water with 1 cup of distilled water. This gives you 1 1/4 cups of 5 ppm phosphate standard water.
7. Mix 1/4 cup of 5 ppm water with 1 cup of distilled water. This gives you 1 1/4 cups of 1 ppm phosphate standard water.
8. Use your test kit to measure the phosphate concentration in each of the 1,5,10, and 25 ppm phosphate standards. If you wish, add the 50 ppm standard to that set.
9. Compare the colors of those to the color card for your kit, and either verify the accuracy of the kit, or use those colors to train yourself to recognize the colors.

Your phosphate test kit is now calibrated. You can store the standard solutions in tightly sealed bottles for an indefinite period of time for future calibrations. Ideally, you calibrate the kit each time you use it.

This can be done for other parameters also like Alk and copper or whatever you wish.

Spoon feeding folks:p

Regards,
Tom Barr
 
Hi Tom you old terd are you lost :wavehand: And welcome to the Reef Chem Forum :D

Nice post but gee guy couldn't you have done that Cup stuff in ml at least :)



For those of you that don't know Tom, he is the FW planted aquarium guru that is always playing with chemicals.


The Tom Barr Report
http://www.barrreport.com/
 
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Dumb question; where can you buy KN03 and/or obtain it? Thx and GREAT info to calibrate your test kit.
 
For me this confirms, again, that API kits are about as good or better than most hobby grade kits. They're easy to use, accurate enough for most of our needs, and best of all they're very reasonable in price. This coming from someone that used only Lamotte for years and then later Salifert. I've been suggesting API for several things for a few years now and continue to be impressed with their value. Thanks for the testing!
 
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