Nitrate Tests - are they all garbage? Round II

[mwp]

So I can't find my original post. We kinda agreed that maybe Nitrate tests aren't all that accurate, but this latest round of "tests" has me more than miffed. What's the DEAL? Here's the scoop:

Last night I utilized 4 different Nitrate Tests to check the nitrate levels in 4 aquariums. All were done within an hour or so; I think these results are pretty "reliable" in so much as each test was tried with 4 different samples, and 4 tests were used. Instructions were followed to the letter (including times of agitation / wait times before reading results)

The tests in question are Seachem, Instant Ocean (brand new test kit), Aquarium Pharm Liquid Test, and Jungle's Quick Dip Strips. Here's the results (all PPM):

Tank #1
SC - 5
IO - 10
AP - 40
QD - 40

Tank #2
SC - 50 or higher
IO - 10
AP - 80
QD - 40

Tank #3
SC - 5
IO - 10
AP - 40
QD - 40

Tank #4
SC - 10
IO - 10
AP - 80
QD - 40

NOT one of these tests acurately matches the results given by another brand of test consistently. Worse still is that the two NEW tests (Instant Ocean 1 part powder and Jungle Quick Dips) gave the same result for every tank tested. It's interesting that these are both "one part" tests. The "two part" tests (Seachem and Aquarium Pharm) gave pretty consistent reading, in both cases showing the differences from tank to tank, yet they don't match up with each other EITHER.

It seems that the one part tests simply don't work even remotely well, as both showed the same results across the board for 4 distinct samples. I don't have any long term data on these two new tests yet.

In looking at long-term data from the two part tests, both seem to accurately track each other's results (i.e. if Seachem shows a rise, AQ Pharm will as well). The problem is that the "distance" between the results is consistently "huge" (i.e. 5 ppm on Seachem vs. 40 ppm for AQ Pharm) and to make matters worse still, at TIMES, these results will almost merge (i.e. getting a 30 ppm on Seachem and still a 40 ppm on AQ Pharm)...the distance between the levels "detected" by these two tests isn't proportional or consistent.

Is there ANY test out there that's a) accurate and b) consistent? I hate having shelled out probably $75+ for 4 nitrate tests only to find myself not really trusting ANY of them!

FWIW,

Matt

[Doni]

Try comparing those with Salifert's test kit.

[the other tang]

I concur. FWIW, I test with Salifert kits, I have used Jungle qd's and they have very similar results. The salifert is more definitive, the qd is a range that is a bit harder to pinpoint an exact level. You can say 10,20 and so on but no closer than that. Bottom line I trust salifert kits. Besides the Owner is a member here and has responded to my posts when I have a question, a nice plus.

[KAiNE]

Agree
Salifert and Lamotte are the only test kits i use.

[mwp]

Looks like I have another round of testing in the works in the next few weeks

Matt

[Hobster]

With the SeaChem test, did you compare it to the reference sample that comes with the kit?

That is the only Seachem test I have used. I use Salifert for Ca, Mg and Alk.

[mwp]

Yeah, I've run references with the 10 ppm Reference on the Seachem test in the past. FWIW, the "reference" is spot on at 10 ppm, so I DO put a little more trust in the Seachem tests than the other ones.

Matt

[mwp]

I just though of this - I could probably use the 10 ppm reference on the other kits as well!!!!!!!!!

Eureka - thanks for bringing this up Hobster - I'll report back with findings when I can!

Matt

[Mooch18]

I use Sera (german) nitrate test kits, and find them to be excellent!!

[reefnetworth]

Salifert and Seachem used to be the only ones i used. now its Seachem only because of the testing (reference) bottle that come with them. the prices are almost identical but its hard to find a LFS that carries Salifert.

John M

[Randy Holmes-Farley]

You might try throwing the Pinpoint Nitrate meter into the mix and see how it does.

[mwp]

Originally posted by Randy Holmes-Farley
You might try throwing the Pinpoint Nitrate meter into the mix and see how it does.

How much is that gonna set me back????

My real dilema is which test is actually showing accurate results. I.e., I'd love to trust my seachem, or maybe the Instant Ocean test (considering that "10" is as low as it goes), which would mean my nitrates are not really a problem in the tanks I'm running. In general though, in all tanks, nitrates have started to climb (depending on which test I use) and are either still safe or not even close (without massive water changes to "control" them)...in any case, just looking for a more solid answer out of my test kits than what I got last night

Matt

[mwp]

Well, gotta love this. Dipped a quick dip strip into the 10 ppm Nitrate Reference that comes with the Seachem test - the Quick Dip Strip was dead on at 20 ppm according to the color charts!

FWIW,

Matt

[Habib]

The IO is the Fastest ? Unless they changed it, they report it as nitrate-nitrogen. Multiply their result by 4.4 to obtain as ppm or mg/L nitrate.

[mwp]

Habib, that's a big "OOOHHHHHH"...was not aware of that. I was just hoping IO was accurate on the basis that all my tanks tested out at 10 ppm, but I guess that's before that multiplication by a factor of 4.4 (meaning all my tanks are at 45 ppm????) While plausible, wait a second, does that mean the lowest range that the test kit can detect is 44 ppm of nitrate? I was already shocked to not see a "0" level available on the color chip (unless a reading of 0 means NO color of any kind develops in the test).

Matt

[Spuds725]

I tested my tank regularly with Salifert and API kits after I added my 29 gallon fuge on my 135 gallon... I tracked my nitrates as they dropped from about 50 ppm to 0 over several months..

I observed the API kit read a little bit lower (5-10 ppm) then the salifert at higher levels, but at lower levels it read a bit higher (about 5 ppm)...

Its kind of hard to compare the two since the reading graduations aren't the same...

Take this any way you want... just my observations...

[mwp]

Picked up the Salifert Nitrate test and ran it.

Tank #1
25 ppm

Tank #2 - 4
All at 50 ppm

Seachem 10 ppm Reference
surprisingly, registered 10 ppm

more soon...

Matt

[Spuds725]

I will add that all the API 40 and over looked the same on the card to me-- there were only subtle changes in the red shade on the card-- very hard to compare with the test kit-- I trusted it more at lower levels and even diluted my tank water with newly made water (1:1) when it was higher to try and see what it actually reading on the API...

The Salifert wasn't much better at higher levels.. shades of purple.

[Habib]

Originally posted by mwp
Habib, that's a big "OOOHHHHHH"...was not aware of that. I was just hoping IO was accurate on the basis that all my tanks tested out at 10 ppm, but I guess that's before that multiplication by a factor of 4.4 (meaning all my tanks are at 45 ppm????) While plausible, wait a second, does that mean the lowest range that the test kit can detect is 44 ppm of nitrate? I was already shocked to not see a "0" level available on the color chip (unless a reading of 0 means NO color of any kind develops in the test).

Matt

They have another one, a low range which starts at IIRC 2 ppm as nitrate-nitrogen so around 10 ppm as nitrate.

[reefworldaq]

Try dilute 50% of water tested with DI water and the result must be multiply by 2. I use Tropic marine and Salifert. See also the expired date (1 year before open and 3 month after open).

[Doni]

Thanks Matt for doing these tests

I must say I am a bit dissappointed with AP... maybe it is the vague color chart?

[Doni]

FYI...

Each AP reagent bottle has a Lot # printed on the bottle. The last four digits are the month and year of manufacture. Example: Lot # 32B0104. This is a pH reagent manufactured in January of 2004.

Ammonia, High Range pH, Nitrate, and GH all last for three years.

Nitrite and KH will last for four years.

Freshwater pH and Salt Level test are good for 5 years.

[jamal-188]

I'm not a chemist...but isn't there a way to make a nitrate titration kit that would change colors like the Salifert CA/ALK kits to give you a more exact number than than matching color charts?

[mwp]

Originally posted by reefworldaq
Try dilute 50% of water tested with DI water and the result must be multiply by 2. I use Tropic marine and Salifert. See also the expired date (1 year before open and 3 month after open).

Not a bad idea. Which test kit is "valid" for only 3 months after opening????!

Matt

[mwp]

Originally posted by jamal-188
I'm not a chemist...but isn't there a way to make a nitrate titration kit that would change colors like the Salifert CA/ALK kits to give you a more exact number than than matching color charts?

I was wondering if there's any titration-style nitrate tests out there as well. Knowing the little bit I know about chemistry, + the fact that NONE of the nitrate test color "shadings" are all that easy to read, well, I'd love to see a titration test.

It's crazy to see the lack of anything really reliable between the 5 tests...almost makes me want to "not care" about my nitrate levels, or just aim for a constant 0 reading on ALL the tests

Matt