API Master Test Kit: Nitrites Test Maybe Faulty

Hi all. New to the forum and new to the hobby in general. Sorry, this is a long post as my first, but I'm got very strong evidence right now that my Master Test Kit is erroneous, and I need someone to look this over.

I am doing a fish-less cycle on my new 125 gallon tank. I have been going for about 6 weeks now. Over the past 10 days or so, Ammonia has finally started dropping regularly, each day, and I dose it back up between 2-4 PPM when it reaches 0. Right now, it's processing down from 4 PPM to 0 PPM in about 1.5 days. So exciting! This is just an aside to my post as you will see below, but is evidence that my tank is at least through part 1 of cycling, Ammonia -> Nitrites.

The Problem
I have tested every day of the past 6 weeks (EXHAUSTING!) for Ammonia, Nitrites, and pH. Except for the last 10 days, Ammonia always present to 4 PPM, 0 Nitrites, 5 PPM Nitrates. In the last 10 days, Ammonia dropping to zero as expected and me dosing it back up (now dropping from 4 PPM to 0 PPM in 1.5 days). Nitrites read 0. Nitrates slowly climbing. I don't know by what voodoo magic I've never seen the Nitrites spike or ever get above zero, but hey, it's what the test kit shows me right? Nitrities been constant light blue all the time in the test tube (API Master Test Kit).

So based on all the research on these forums and elsewhere, sounds like I got myself a cycled tank. Just a few more days and I can finally get some fish in there. Ammonia is going away. Nitrites are 0. Nitrates slowly climbing! I call my LFS to put in an order for some Silver Dollars I want to start with (plan to stock slowly of course), and good. (This was today, 2 hours ago)

The problem is, I have evidence now that the API Master Test Kit might be lying to me about the Nitrites! I don't think it's 0. I think it's off the charts (spiked). I also have stronger evidence the pH test is also not reliable.

The Story / Evidence

Meantime, I've been dealing with pH problems both in my new 125 gallon, my 55 gallon (which I got months ago is cycled and stocked), and ironically, my Hot Tub (I guess I love water!). The problem according to research with my pH is that water is just super soft, and barely has any carbonates, so it's very "moody" when it comes to pH. This bears out when i test my tap water, very soft, low carbonates. I love my fish, so I'm constantly tinkering with things on the pH side of the house because my water seems to naturally want to creep up to around 7.8 - 8.0 PPM (which I can't explain since low carbonates and soft... and it comes out of the tap at 6.8 and stays that way for days... i've tested it). I've been slowing adding Peat Moss to my 55 gallon to keep the pH more in line with how my tropical fish like it, and to make sure it stabilizes and doesn't swing so much. That's working great!

Right after I get off the call with my LFS, I had just tested 0 Ammonia, 0 Nitrites, and midling Nitrates, and I'm super stoked to get some fish. I say "self, haven't tested pH today"... so I test. Immediately, pH in my 125 gallon reads off the chart purple. Well over 8. I'm immediately alarmed! What the heck? It was fine yesterday! This is crazy pills. Let me test it one more time. I test again. This time pH reading is 7.2 (high Ph on master test kit reads bottom "brown"). What the heck? Two tests, back to back. One comes back off the charts. One comes back "fine". "OK, ok, I must have screwed up the first test? Maybe i picked up a rogue ammonia partricle? Crazy pills, but I'll solve this. pH test number 3!" So test 3, comes back 7.2, just like test 2. "Ok, I don't know what happened with test 1. Just a fluke I guess?"

Is my master test kit bad? This is not the first time it's come back solid purple on pH and got me into a panic for me to discover later it's fine.???? It's happened one other time in my 55 gallon!

OK I got this. Months ago when I bought my 55 gallon, I had bought test strips at the same time. (Later realized everyone uses the Master Test Kit because it's more reliable so bought that instead). Let's see if the Test Strip agrees with my Master Test Kit! I pop open the bottle, pull out the exactly last test strip in it (frustratingly important as I write this), and I stick in the 125 gallon tank.

Results from Test Strip:
Ammonia: 0 PPM. Check. Master test kit agrees as does my Seachem Ammonia Alert monitor sitting in the tank! 3 Tests all agree.
ph: 7.4. Check. Master test kit I think is 7.2 but it's close, whatever! Why did my first test come back solid purple?? What is going on with this Test Kit??
Nitrates: 40 PPM. Higher than my master test kit, but variance. Seems OK.
Nitrites: 10+ PPM (off the scale high!) ****? Unmistakably red reading. Master Test Kit = Light Blue, 0 PPM. OK between this and pH test, now I'm super concerned.

!!!!! I just ordered some fish, and the Test Strip says my water is a toxic death pool of Nitrites !!!!

What is going on? Master Test Kit been light blue since day 1. Never faltered.

Google "is master test kit nitrite test faulty". Start getting back results that if the Nitrites are high, it can be faulty, but the way everyone describes it being faulty is that as soon as the drop droplets in, the tube starts Purple (very high) and slowly goes to Light Blue. Mine is Light Blue, 100% of the 5 minutes.

But, I've never seen the Nitrite spike either! So, the Ammonia is going somewhere? And yes, my Nitrates are going up. So, I'm thinking "everything is working. It's odd, but 'fits'" till I hit that test strip!

As of the moment of this writing:
- I can't test again with another test strip because I'm out! Frustrating lol. Ordered some and waiting.
- I tested Nitrites again and again and again. 0 PPM on the master test kit, light blue.
- I then said "OK maybe the Nitrite test on the MTK is just not very good when it's too high?" So, I took Tap Water, tested Nitrites, also 0, Light Blue. Then I took 75% Tap Water + 25% Tank Water, tested Nitrites, still 0. Then 90% Tap Water + 10% Tank Water and 25% Tap Water + 75% Tank Water. (I'm doing this because if the MTK test fails when Nitrites are super high, diluting the water should help me know!) All 0 Nitrites. All Light blue.

My next step will be a big water change, 50%+, and then get a reading. But at this point, I think my MTK is faulty, so my reading will be faulty.

Anyone seen this before? Have any suggestions?

 

I didn't read your entire long post, but a cycled tank should have a reading of at least 5. 0 nitrates means that your tank isn't cycled yet.

 

I didn't read your entire long post, but a cycled tank should have a reading of at least 5. 0 nitrates means that your tank isn't cycled yet.

Yeah sorry, you'll have to read it through as this is complicated. I don't have 0 nitrates. I have 0 nitrites. Different problem.
Update:

I just got ahold or more test strips. Different brand name.

Tested 125 Gallon Tank:

Ammonia: 0 PPM Agrees with all other tests.
Nitrites: 10+ PPM (off the chart). Agrees with previous test strip. MTK reads 0 PPM still.
Nitrates: 40 PPM. Agrees with all other tests.
ph: 6.4 Water go really acidic in the last 3 hours, but all tests agree.

As a result, I believe at this point, the API Master Test Kit's ability to detect Nitrites is compromised. Either it's faulty, or it never worked.

 

Update

50% water change.

Master Test Kit:
Ammonia: 0 PPM
Nitrites: 0 PPM
Nitrates: 20 PPM (expected after 50% water change when it was 40 PPM prior)

Test Strip
Ammonia: 0 PPM
Nitrites: 10 PPM (looks different now after water change instead of being "off the scale" looks like top of scale... no longer hot pink and instead the orange/pink that is on the scale at 10 PPM)
Nitrates: 20 PPM

Since the Test Strip changed its Nitrite reading after the Water Change, and OF COURSE having a Nitrite spike is expected once the Ammonia starts cycling, seems now that it's undeniable that the MTK's Nitrite Test is faulty.

So anyways, I hope this helps someone else as if the MTK test can be faulty and it is so highly recommended, I can't be the only person with this problem.

Takeaway:
MTK Nitrite Test is unreliable.

MTK pH Test should be retested if you get sudden, abnormal results.

 

I also did not read the entire post, but (if I remember correctly) inconsistent PH levels can affect the reading of nitrites in test kits, so I would make sure your PH stays at a certain level while doing tests. It's also possible that your nitrite test in the master kit is faulty, it happens sometimes. That's why if you ever have any doubts (like you do now) you always want to have a backup test kit either test strips, or a different brand test kit.

 

I had a MTK that had ammonia bottle that no longer worked. Confirmed after I got new kit. You can always order a separate Nitrite bottle to test/confirm your suspicions It's about $11. If your nitrates are ending up at 20 PPM with the amount of ammonia you are starting out with, then to me, I don't think it's a huge concern. Unless your nitrates are giving you a false reading...

 

I had a MTK that had ammonia bottle that no longer worked. Confirmed after I got new kit. You can always order a separate Nitrite bottle to test/confirm your suspicions It's about $11. If your nitrates are ending up at 20 PPM with the amount of ammonia you are starting out with, then to me, I don't think it's a huge concern. Unless your nitrates are giving you a false reading...

Thanks for that! It's good to know that the MTK can be faulty as experienced by others to validate that I'm not on crazy pills to think that it might be busted. I guess the rule is, need multiple water tests so you can validate that any given one is working as expected.

My Ammonia Test on the MTK agrees with both Test Strip and Seachem Ammonia Alert. So, I'm strongly confident in those results.

My Nitrates Test on MTK agrees with Test Strip. So, I think I'm good there.

My Nitrites on MTK is obviously busted. Glad I found this problem else I would have dead fish right now.

My pH test on MTK is suspect. It seems to be corroborated by Test strips for the most part. But twice now I have gotten results from low/high test that the pH had crazy basic spikes (well over 8), and now I'm suspect of the pH test as well. Back to back testing, although physically possible that I had a huge pH spike and then a drop off within minutes seeks dubious. If I ever see the spike again off the MTK I'll immediately corroborate with a Test Strip and see if they agree.

 

Not sure what's going on with the tests, but have you tried adding some shrimp or snails to see how they do? 10ppm+ nitrite should be evident immediately just by looking at the livestock

 

I don't think you're on crazy pills with the nitrites in the MTK. API is not fond of admitting it but if you send photos of the differing test results, sometimes they'll replace the faulty test. What I've found is that the 'uniform drops' we're so careful to measure are coming from API bottles with inaccurate bore sizes: dropping twice the amount needed for example or 1/2. My particular bug bear is the MTKs that tell me all about the ammonia in distilled water. Switch over to Seachem or another product & of course, neither distilled water or my tanks have screwy readings. However, the API test drops are most easily available to me. As a result, there are times that the kit is clearly faulty & I just carry on, ignoring APIs take on that parameter. It's happened with enough API test kits over the years that I kinda expect it.

Good luck stocking & enjoying your newly cycled tank.

 

Not sure what's going on with the tests, but have you tried adding some shrimp or snails to see how they do? 10ppm+ nitrite should be evident immediately just by looking at the livestock

Haven't tried it, no. But, definitely my test strips light up like bright red on the Nitrites while the MTK stays blue (0). My understanding is, I SHOULD have Nitrites, being that I just started processing Ammonia down about 10 days ago, and that's not, according to my reading, enough time for the bacteria colony to really get in there to handle the Nitrite -> Nitrates. There's definitely some bacteria in there, because my Nitrates are slowly going up too, but definitely not enough.

*shrug* I'm just resigned to that test on the MTK being bad. Strips seem to tell the real story on the Nitrites and that's good enough to keep me going.

I don't think you're on crazy pills with the nitrites in the MTK. API is not fond of admitting it but if you send photos of the differing test results, sometimes they'll replace the faulty test. What I've found is that the 'uniform drops' we're so careful to measure are coming from API bottles with inaccurate bore sizes: dropping twice the amount needed for example or 1/2. My particular bug bear is the MTKs that tell me all about the ammonia in distilled water. Switch over to Seachem or another product & of course, neither distilled water or my tanks have screwy readings. However, the API test drops are most easily available to me. As a result, there are times that the kit is clearly faulty & I just carry on, ignoring APIs take on that parameter. It's happened with enough API test kits over the years that I kinda expect it.

Good luck stocking & enjoying your newly cycled tank.

Thank you for corroborating that. Feels much better. I will definitely double test anytime I get a new kit or elsewise to see what all works and what doesn't.

Just for giggles, I just ran a test, thinking about your comment on the bore holes. Put 3 drops in one (a little over half) and 10 drops in another (double the amount). Result is both just blue (one more blue than the other) and eventually run clear. I'm pretty sure whoever made my MTK just put blue food coloring in my nitrite test for jokes, haha.

Anyways, thank you for that. I'll wait till the Test Strips read 0 Nitrites (probably got many weeks ahead unfortunately!) and then see about those fish, FINALLY haha.