A test of Nitrate Test Kits
- Thread starter Billybeau1
- Start date
I TAKE PINPOINTS nitrate cal solutions 1ppm and 10ppm and cut the 1ppm down to .5 and have tested a number of reefers in my club with seachems test and awt and for nitrates 5ppm and under seachem and awt are right on............so what am i soppose to take from this but that seachem is one great test in the low randge and super cheap to boot.......how can pinpoints nitrate cal solution not be accurate.How can both awt and seachem come back the same with 6 different tanks.
Billybeau1
Premium Member
Oh boy........ steve, I have answers to your questions but I need a few weeks to finish my testing. I want to make sure my facts are straight before posting. When I get my testing concluded, you will have answers to your questions, I'm sure. I've spent a lot of time on this project. 
I can tell you now that I do not care for AWT's testing methods and I certainly am not impressed with the Seachem nitrate test kit, for a number of reasons.
I will state my case soon.
I can tell you now that I do not care for AWT's testing methods and I certainly am not impressed with the Seachem nitrate test kit, for a number of reasons.
I will state my case soon.
Steve
I stand behind Billy. There is something going on here that nobody knows about but us and it is going to require some time with more testing. When it is done Billy will give the reasons and why. I can tell by just reading your post you have a big error there in the way you are testing. Billy knows what I mean.
I stand behind Billy. There is something going on here that nobody knows about but us and it is going to require some time with more testing. When it is done Billy will give the reasons and why. I can tell by just reading your post you have a big error there in the way you are testing. Billy knows what I mean.
Frogmanx82
New member
So where does the 5 in 1 test strip rank in all this. It couldn't be any easier and seems to show some color change at fairly low nitrate levels. Of all the parameters on the test strip, the only one I look at is the nitrate. It seems to me to be quite sufficient for detecting nitrate issues.
Billybeau1
Premium Member
I've never tested strips. I can't imagine they can be very accurate but who knows.
When i stopped dosing volka My nitrates jumped up to 2 for a while i tested my 2ppm reading i got from seachems test with awt and most of the kits you talk about here[except lamottes] and they all picked up some nitrates.
2 MONTHS LATER my nitrates dropped back under 1ppm awt [.6] seachem around this and all the others showed no nitrates.
Help me understand what you guys are trying to say because i dont care if my nitrates are 1ppm or .5 ppm this is accurate enough for me.
For nitrates around 1ppm this test and awt is fine to me.
The difference between 20ppm and 40ppm would concern me but this test and awt picked up my increase in nitrates and then picked up my decrease so explain youR point please.
I RESPECT your opinions very much so can YOU fill me in and i mean for testing around 1ppm..........thanks guys
2 MONTHS LATER my nitrates dropped back under 1ppm awt [.6] seachem around this and all the others showed no nitrates.
Help me understand what you guys are trying to say because i dont care if my nitrates are 1ppm or .5 ppm this is accurate enough for me.
For nitrates around 1ppm this test and awt is fine to me.
The difference between 20ppm and 40ppm would concern me but this test and awt picked up my increase in nitrates and then picked up my decrease so explain youR point please.
I RESPECT your opinions very much so can YOU fill me in and i mean for testing around 1ppm..........thanks guys
Frogmanx82
New member
I've never tested strips. I can't imagine they can be very accurate but who knows.
I think you would be surprised how well they work for nitrate. You can certainly tell if you have 10 ppm or more. If I have no color change on the strip, I know I'm in good shape.
Steve
I'll give you this for now OK. First there are different ways for testing Nitrate, ISE probes, Photometer and test kits. Probes and spectrophometers are sensitive to salinity and must be calibrated using seawater nitrate stds. Meaning, FW stds do not work right. If you do not use the proper std they will be off. Test kits can be the same buy not by as much. Some use FW stds for kits or meters/probes for seawater and some do not. Nitrate can be expressed two different ways, i.e., N-NO3 or NO3-. 1 ppm N-NO3 does not equal 1 ppm NO3-. Some kits meters etc, may be getting calibrated or ref to with a FW Std as N-NO3 std but the kit meter is expressing the Nitrate as NO3- and not N-NO3. Some maybe cal ref to a seawater std for N-NO3 and expressing it as NO3-. And on and on. You can see what kind of mess this can led to. Many kits, meters are affected this way, but some are not, it depends on what ion you are testing for. Some tests are subject to what is called the "salt effect" error.
A good example is pH. All meters are affected by the salt error and so are many test kits. This is often the case when comparing test kits from one to another or against a meter. You ask yourself the question why is one 8.00 pH and the other 8.3 pH. Well, one is correcting and one is not. And then there is the other issue. We and most books and articles do not correct for pH. You only see corrections in advanced books or articles on pH. So, for us and almost all others, even in other fields, it is not a concern. But that kit or meter that we may be using, if it is corrected, is a concern and we need to know. So, the end of the store is in pH measurement we are more or less all on the same page but not for such things as Nitrate. I feel AWT, that uses a spectro or meter and Seachem using a kit, are in fault and others are not and why you are getting the readings you are. We are trying to see what is what here.
Fox
I think you would be surprised how well they work for nitrate. You can certainly tell if you have 10 ppm or more
I would only be surprised if this test strip was tested against a seawater ref std of 10 ppm NO3- Nitrate Ion And how is that test strip expressing Nitrate, as N-NO3 or NO3 ?
I'll give you this for now OK. First there are different ways for testing Nitrate, ISE probes, Photometer and test kits. Probes and spectrophometers are sensitive to salinity and must be calibrated using seawater nitrate stds. Meaning, FW stds do not work right. If you do not use the proper std they will be off. Test kits can be the same buy not by as much. Some use FW stds for kits or meters/probes for seawater and some do not. Nitrate can be expressed two different ways, i.e., N-NO3 or NO3-. 1 ppm N-NO3 does not equal 1 ppm NO3-. Some kits meters etc, may be getting calibrated or ref to with a FW Std as N-NO3 std but the kit meter is expressing the Nitrate as NO3- and not N-NO3. Some maybe cal ref to a seawater std for N-NO3 and expressing it as NO3-. And on and on. You can see what kind of mess this can led to. Many kits, meters are affected this way, but some are not, it depends on what ion you are testing for. Some tests are subject to what is called the "salt effect" error.
A good example is pH. All meters are affected by the salt error and so are many test kits. This is often the case when comparing test kits from one to another or against a meter. You ask yourself the question why is one 8.00 pH and the other 8.3 pH. Well, one is correcting and one is not. And then there is the other issue. We and most books and articles do not correct for pH. You only see corrections in advanced books or articles on pH. So, for us and almost all others, even in other fields, it is not a concern. But that kit or meter that we may be using, if it is corrected, is a concern and we need to know. So, the end of the store is in pH measurement we are more or less all on the same page but not for such things as Nitrate. I feel AWT, that uses a spectro or meter and Seachem using a kit, are in fault and others are not and why you are getting the readings you are. We are trying to see what is what here.
Fox
I think you would be surprised how well they work for nitrate. You can certainly tell if you have 10 ppm or more
I would only be surprised if this test strip was tested against a seawater ref std of 10 ppm NO3- Nitrate Ion
And how is that test strip expressing Nitrate, as N-NO3 or NO3 ?Frogmanx82
New member
Boomer, I think you are too hung up on the absolute number. For the most part people are just looking for changes. It doesn't matter if my bathroom scale if off 5 pounds as long as I use that scale all the time. The absolute accuracy is less important than understanding what is changing.
The problem comes of course when your comparing different scales and trying to know what the set point should be on your test method. For pH this is a larger issue than nitrate. We know the nitrate target is 0.
The problem comes of course when your comparing different scales and trying to know what the set point should be on your test method. For pH this is a larger issue than nitrate. We know the nitrate target is 0.
Billybeau1
Premium Member
Not necessarily. I've actually seen some reefers trying to add nitrate to accomplish a balance in their reefs. This can get complicated.
Frog
Not really so for some
I should have added this
1 ppm N-NO3 = 4.4 ppm NO3
So, if you have a meter or kit that reads 5 ppm N-NO3 it is really 22 ppm NO3-. And as you can see that is allot. And if you cal that NO3 meter say with N-NO3 std it will be a mess. A SeaTest Kit and a LaMottt, measure it as N-NO3 for example and if they read 1 it is really ~ 4.5. Are you happy with that ? For a while, till I got after Deltec, they were selling Phosphate kits that tested really low. All where running out to buy it, as they testd much lower than others. Till, I pointed out, it was not measuring PO4 but P-PO4. 1 ppm P-PO4 = ~ 3 ppm PO4. Now, they have noted that in their instructions. I'm not looking to be exact Frog it is being way off
Not really so for some
I should have added this
1 ppm N-NO3 = 4.4 ppm NO3
So, if you have a meter or kit that reads 5 ppm N-NO3 it is really 22 ppm NO3-. And as you can see that is allot. And if you cal that NO3 meter say with N-NO3 std it will be a mess. A SeaTest Kit and a LaMottt, measure it as N-NO3 for example and if they read 1 it is really ~ 4.5. Are you happy with that ? For a while, till I got after Deltec, they were selling Phosphate kits that tested really low. All where running out to buy it, as they testd much lower than others. Till, I pointed out, it was not measuring PO4 but P-PO4. 1 ppm P-PO4 = ~ 3 ppm PO4. Now, they have noted that in their instructions. I'm not looking to be exact Frog it is being way off
2thdeekay
New member
For a while, till I got after Deltec, they were selling Phosphate kits that tested really low. All where running out to buy it, as they testd much lower than others. Till, I pointed out, it was not measuring PO4 but P-PO4. 1 ppm P-PO4 = ~ 3 ppm PO4. Now, they have noted that in their instructions. I'm not looking to be exact Frog it is being way off
Boomer, I was wondering about that. When did this change come about? Thanks!
Frogmanx82
New member
Boomer, I appreciate your efforts in helping people understand what they're testing. Also important is for people to understand why they are testing and what they are going to do with the test results.
I USED THE REFERENCE SAMPLE that comes with the seachem kit with other members kits[most of what you tested] and they were all around 10ppm as best you can read these things so i think you guys are splitting hairs.
for our hobby these kits work good and they are cheap......my favorite is still the seachem.
If my nitrates are really 4ppm and not .6 who cares as long as i can spot a change for the worst......MY 2 CENTS:eek1:
for our hobby these kits work good and they are cheap......my favorite is still the seachem.
If my nitrates are really 4ppm and not .6 who cares as long as i can spot a change for the worst......MY 2 CENTS:eek1:
emoore
New member
I disagree. I want to know if my nitrates are 4.4 times off. I think it is a really big deal if my test kit is reading 5 ppm but it is really 22 ppm. I have been using the Salifert nitrate kit but I think I will switch to LaMott.
2thdeekay
New member
:eek1:
Steve, I'd like to politely comment that posts like that on a "reef chemistry" forum can start a fire. LOL Many folks here enjoy water chemistry more than reefing, as it's a hobby in itself. However, I do agree with you regarding not expecting too much from an inexpensive hobby kit.That said, I'm very satisfied with the Salifert NO3 Kit. The low range seems to work just fine for reefing purposes, 0.2 - 10 mg/L as Nitrate, not N-NO3.
luther1200
Premium Member
+1
emoore
For low readings you may want to stick with the Sailfert, as it is NO3. The LaMotte is N-NO3 and only goes down to 0.2 N-NO3 x 4.4 = 0.88 ppm. Or this kit made for seawater
http://www.nitrate.com/sw-ntk2.htm
Ultra Low Nitrate Analysis
0.5 µM - 10µM Nitrate = 0.007 ppm - 0.14 ppm N-NO3 ( x 4.4) = 0.03 ppm - NO3- 0.62
For low readings you may want to stick with the Sailfert, as it is NO3. The LaMotte is N-NO3 and only goes down to 0.2 N-NO3 x 4.4 = 0.88 ppm. Or this kit made for seawater
http://www.nitrate.com/sw-ntk2.htm
Ultra Low Nitrate Analysis
0.5 µM - 10µM Nitrate = 0.007 ppm - 0.14 ppm N-NO3 ( x 4.4) = 0.03 ppm - NO3- 0.62
