A test of Nitrate Test Kits

Billybeau1

Billybeau1

Premium Member
A little while back I found many reefers trying vodka dosing to reduce Nitrate and Phosphate levels. So I decided it was time to test nitrate test kits as this seems to be the method of gauging the effectiveness of dosing a carbon source.

I am a little disappointed at the final results of my test. But I will post them anyways and let you all draw your own conclusion.

I purchased 8 hobby grade test kits.
LaMotte
Salifert
API
Seachem
Elos
Tropic Main
Red Sea
Sera

All above tests reported results in NO<sub>3</sub>, except LaMotte. These results are in NO<sub>3</sub> - N (nitrate- nitrogen). All LaMotte results are multiplied by 4.4 to get nitrate ions.

I first tested each kit with my ro/di to make sure there was no NO<sub>3</sub> in my fresh water. No kit registered any level of nitrate in my water.

I then tested the nitrite level of my tank as elevated nitrite can skew some nitrate test kits. No kit tested higher than .02 ppm of nitrite. I believe this will be ok for our test.

Now, keep in mind, my tank has a nitrate level of over 100 (I believe). I have a Fish Only and the fish do not seem to mind much. :D

So, my first test was with a full sample of my water.

LaMotte = Over the scale. Unable to determine.
Salifert = Over the scale. Unable to determine.
API = 140 ppm
Seachem = Over the scale. Unable to determine.
Elos = Over the scale. Unable to determine.
Tropic Marin = 100 ppm
Red Sea = Unable to determine
Sera = 40 ppm

My next test was to dilute my sample 50/50 and see what it read.

LaMotte = unable to determine
Salifert = 35 ppm
API = 60 ppm
Seachem = 50 ppm
Elos = unable to determine.
Tropic Marin = 50 ppm
Red Sea = 60 ppm
Sera = 15 ppm

I then diluted the sample 10 to 1. I wanted to test each kit at the lower end of the scale since it seems most hobby grade kits are geared towards that. And since most reef tanks have much lower trates than I do.

LaMotte = 17.6 ppm - my tank - 176 ppm
Salifert = 10 ppm - my tank - 100 ppm
API = 15 ppm - my tank - 150 ppm
Seachem = 15 ppm - my tank - 150 ppm
Elos = 15 ppm - my tank - 150 ppm
Tropic Marin = 15 ppm - my tank - 150 ppm
Red Sea = 5 ppm - my tank - 50 ppm
Sera = 5 ppm - my tank - 50 ppm

General thoughts about each kit.

LAMOTTE
I love this kit. Initially a little more expensive than most but refills are not too bad. I love the color comparator. Although it read a tad higher than other kits, it is still in the ball park. Very user friendly. I give it 4 thumbs up

SALIFERT
Color chart is hard to read at low and high levels. Test is easy enough but results are inconsistent. I give it 2 thumbs up

API
This test does extremely well at high levels of nitrate but does poorly at low levels due to the color increments of the color chart. I recommend this highly for tanks with higher levels of nitrates but do not recommend it for low level testing. I give this 3 thumbs up

SEACHEM
I'm not much of a fan of many Seachem test kits but this one seemed to preform pretty well at low range testing. It is easy to use and the color chart is pretty nice with the slide indicator. It also doubles as a nitrite kit. I give this kit 3 thumbs up

ELOS
Forget this kit for high level testing (over 25 ppm) but low level it matched Saliferts. The color card is easier to read than Saliferts and the kit is easy to use. I give this kit 3 thumbs up

TROPIC MARIN
This kit actually measures high nitrates quite well. I was impressed with the kit itself as well as the instructions. Very easy to use. It also doubles as a nitrite kit. 2 for the price of one. I give this kit 4 thumbs up

RED SEA
This kit has an easy to read color chart but the results as just not consistent with the other tests. I give this kit a :thumbdown

SERA
This test kit shows the ability to test in a variety of ranges up to 400 ppm. Unfortunately, a variety of tests showed many inconsistencies in the results. I give this kit a :thumbdown

Prices vary for these test as do tests per kit.

Lamotte = $56 , refills about 20 bucks - # of tests not listed
Salifert = $20 - 60 tests
Elos = $28 - # of tests not listed
Seachem = $13 - 75 tests
Tropic Marin = $20 - # of tests not listed
API = $8 - 90 tests
Red Sea = $13 - 60 tests

Summary

I am a little disappointed as I thought the numbers would be a little more linear in the dilution stages. I guess that is why they call them "hobby grade" test kits. It does appear, however, that a number of these kits do quite well at the low levels of nitrate you are all striving for. As for an exact number, I doubt any of these kits are going to provide that.

:)
 
Lamotte = $56 , refills about 20 bucks - # of tests not listed

40 tests /refill

Red Sea

I played with that test when testing Lou' s Nitate meter and hated it :(

I am a little disappointed

Don't be, as testing for Nitrate and getting accurate reading can be an issue, These kits use Cadmium reduction, where NO3- is converted to NO2-. The only one we may use in this hobby better than the LaMotte is the HACK NI-14 @ 2x $ the LaMotte. I will add that the Elos kit has been tested by ENC Labs for accracy and is pretty much on.

I should have told you when we talked :( to go to HACH and get at 10 mg/ l N-NO3-( 44 ppm as NO3-) NIST std or get some of Lou's std for his Nitrate meter for seawater, 1, 10 and 100 ppm NO3-

http://www.hach.com/hc/search.produ...-N+(NIST),+10+mg&frasl;L,+Bottle&frasl;500+mL
 
:lolspin::lolspin::lolspin:

I was just looking for those tat and my old link was dead so gave up on it :) You to have to reg and for that pdf one.
 
Gotta agree

Thanks Billy

Looks like I'll give the Lamotte a try. I use the Lamotte for Alk and love it.
Salifert hard to read below 10 ppm.
 
iFisch said:
Billy, we appreciate your time and money put into this test. Great job. :beer:
Click to expand...

+1; outstanding post and thx for spending the time and $$$ to help us all out. I will continue to test my tank on a weekly basis with Salifert, API and Elos and try my best to post results along the way.
 
iFisch said:
Billy, we appreciate your time and money put into this test. Great job. :beer:
Click to expand...
Agreed 100% ! Thank you very much!

Now that you have these kits, one interesting experiment could be to test which kit detects lowest amount of NO3. In my opinion the detection limit is more important than absolute accuracy.

Maybe try 1:1000 dilution :)
 
And BTW, these kinds of tests would be excellent material for the Reefkeeping Magazine. They might even pay for the kits :idea:
 
I always liked my Salifert kit the best. You can look throught the side if its under 10 and it makes it much easier. But I'm sure everybody knows that. Are those other kits really that much better?
 
I don't know Matt. I could not test these kits at ultra low levels of nitrate for obvious reasons. I may have been a little hard on the Salifert. I know many use them and most have extremely low nitrate levels so it may be easier to read.

I may run one more test even diluting my sample even more. Although I am of the opinion that any tank below 10 ppm is in pretty doggone good shape. :D

I can tell you I loved LaMottes color comparator. It is pretty easy to tell the color differences on the scale. It measures as low as 1.1 ppm and goes from there 2.2, 4.4, 8.8, 17.6, 26.4, 35.2 and 44 If I had nitrates below 40 ppm, I would love this kit. I think it is worth the money. :)

And I liked the Tropic Marin because it did equally well at high levels as well as low levels.
 
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