High nitrite but Ammonia and Nitrate say I'm cycled

[KrystaWB]

Hi everyone... I have a fair amount of experience with aquariums but have been out of the hobby for about 10 years and just recently got back in.

I have a 15 gallon Fluval Flex (which I love) in my office that has been up and running for several weeks. I thought it was fully cycled but my water tests are confusing me... here are today's results:

Ammonia = 0
Nitrite = 2.0
Nitrate = 5-10ppm
Ph = 7.4

the tank has a few fish in it already, not overstocked at all, and I have been doing weekly water changes since the setup is still fairly new. It is also a planted tank (first time with live plants!).

here is the issue - I CANNOT get the Nitrite to go down... no matter what I do it seems to stay at 2.0ppm.

I am using the API Master Test kit and then numbers in our other tank are fine (as far as I know as I don't test that tank my BF does). Is it possible there is Nitrite in my tap water supply?

I do use water conditioner (Nutrafin AquaPlus), I have added Cycle and the Fluval bio-suplement (as I ran out of Cycle). and I have just added some Fritz Complete as it is supposed to neutralize the Ammonia/Nitrite/Nitrate. I also threw in a NitraZorb pouch which has now made my water cloudy (but it seems to be slowly clearing) All my fish are acting just fine.

Thoughts? Anything else I can try? this is very frustrating

[Aiken Drum]

You arent cycled.

The ammonia to nitrite stage is sufficient to cycle out all the ammonia your fish produce into nitrite, but your nitrite to nitrate stage isnt. There is enough bacteria to process some nitrite into nitrate, but not all of it. This is why you see 0 ammonia, and some nitrite and nitrate. Most cycling tanks would go through a similar set of water parameters.

When you say you can't get nitrite down no matter what, do you mean even a water change doesnt bring it down? Are you seeing 2ppm immediately before a water change and the same reading immediately afterwards? If so, have you tested your tap water?

2ppm nitrite is very harmful for your fish, you really need to bring it down to below 0.5ppm otherwise your fish will start to suffer from nitrite poisoning and organ failure. Assuming your tap water is 0ppm nitrite that would take 2 x 50% water changes. Do the them a couple of hours apart. Until your cycle has established test your water daily, if nitrite is above 0.5ppm then change some water to bring it down.

[KrystaWB]

good points... I am going to first test my tap water to rule that out as a possible source. I did a water change yesterday (about 20% or so) but I didn't test... and then today after I tested I did another water change. I will give it a couple of hours and then test again and if my nitrite is still high I will do another water change. and then continue on

[KrystaWB]

forgot to mention - the other weird thing is that on Jan 31 my Nitrate was 10... but ever since it has been down at 5ppm...

[Aiken Drum]

20% water changes isnt enough to notice a difference in test results. Lets say your nitrite is 2.0ppm. A 20% water change will bring it down to 1.6ppm. You cant tell 2.0ppm from 1.6ppm, the test isnt that accurate. You need bigger water changes to have a noticable effect on parameters and keep your fish safe from waste. And you probably just need to wait things out until your cycle establishes. You arent seeing anything out of the ordinary.

[Aiken Drum]

Originally Posted by KrystaWB

forgot to mention - the other weird thing is that on Jan 31 my Nitrate was 10... but ever since it has been down at 5ppm...

Testing isnt all that accurate. Its a home test kit, not laboratory testing. All sorts of things can effect these tests, especially nitrate, which i understand water companies with professional tests in labs find difficult to test for. One of the things that can throw off nitrate tests is high nitrite. You have low ammonia (possibly zero), moderate nitrite and low levels of nitrate. Thats about all you can take from your tests.

[KrystaWB]

all good points... I have been out of the hobby for ~15 years or so and I have just forgotten alot of this stuff. and you find so many conflicting opinions out there... off to test my tap water, my tank water and then probably do a huge water change... I am just worried about stressing out my fish too much especially my betta Mr. B

[Aiken Drum]

15 years ago not as much was understood about the nitrogen cycle and cycling tanks as it is now. And there is still a lot of unknowns or at least open for debate. You can read through historic posts on this forum and see increased knowledge and understanding over time.

Some of the conflicting opinions may just be reading old information thats still out there. Also many people who have been in the game a lot longer than i have will give you different opinions and it will be what works for them. There are certainly more than one way to skin a cat, and opinions and processes will vary from one hobbyist to another and can also change over time. Im sure come back in another 15 years and things will have moved further forward.

[KrystaWB]

as with everything things change over time... I test my tap water and it has 0 nitrite... I then tested my tank again and it had come down some but not enough so I am now doing another larger water change. should I leave a few hours between water changes or just do them back-to-back? and then once it's acceptable when should I test again? 24 hours?

[Aiken Drum]

If you are worried about water changes stressing fish change 1/3 and then another 1/3 a few hours later. Honestly though, if you do your water change right, then 2 x 50% water changes shouldn't cause stress.

As said, until your cycle establishes and you consistently see 0ppm ammonia and nitrite then test daily. If your test shows ammonia + nitrite combined above a target of 0.5ppm (say 0ppm ammonia and 0.75ppm nitrite, 0.75ppm combined) do a water change to get it below the 0.5ppm combined target.

[KrystaWB]

Thanks for your advice - I did a big water change (~50%) and retested and my nitrite is down to 0... I will test again tomorrow and go from there

[Joe_D]

15 years ago not as much was understood about the nitrogen cycle and cycling tanks as it is now.

Yes, back in the 1970s when I first got into Aquariums, all we were told to do is check water PH.

When I got back into it recently, I found that its whole new world of water chemistry which we now have to be aware of