Nitrite and cycling issues in cycled media. (Need pro advice)

[The.WishMaster]

Hi All,

I am having a weird problem with my tank. I have had a tank running (180L) since 2 years. Pretty stable etc. I started a 450L tank and used the same media and more seeded media in a bigger filter with the same fish load and added bacteria starter liquid as well. The tank ran fine for 2 months. I added some more fishes in it and suddenly I had a massive wave of death in my tank. I tested the parameters and saw that the nitrites were off the roof.
I did 90% water change daily and added stability and Sera Nitrite Minus daily, however the daily readings are not going below 0.25ppm for Nitrites. Even after 80% water change I still see 0.025 or higher nitrite levels. Ammonia is 0 since the beginning.

Now I am wondering why that is it not going down whatsoever. I am missing a few big fishes that I haven't seen since 4 weeks or so since its a heavily planted tank, I am wondering what can be causing this?

Tank is running since 3 months, shouldn't it have cycled by now even with new media even if I hadn't added seeded and matured media in it?
Is it those 3-4 missing fishes that may have died that could be causing a constant nitrites?
Are water changes causing it to not cycle properly?
I have Purigen pouch in my filter, can that be causing it?
I run Co2 (1BPS) for 7 hours. pH fluctuates between 7.6-7.3
Aquasoil as substrate

What is the solution here for me?
I have lost 70% of the fishes already that were alive since 2+ years. I need help.
Water changes for a 450L every 2-3 days is really not feasible for me anymore 🙁

 

[nijat11]

I had the same issue when I started my aquarium. My personal experience the cycled media does not make instant cycle, but it definitely can help. When you added fish, probably you increased bio load and filter was only cycled for level of bio load that you had before. And the main thing if you have ada aquasoil it release insane amount of ammonia in first 5-6 months, because of that I also lost a lot.
So what you could do, monitor the level of nitrite and increase stock slightly. As I said before if you have ADA, the cycle tooks months, for mine 800l, it took around 4 months. And dont and any liquid bacteria, just waste of money.

 

[The.WishMaster]

But how to get the Nitrites down when even the water change is not doing it fully

 

[Connswater]

70% is a huge loss, what distress symptoms have you witnessed? Is there a time in the rhythm of the photo period/dark period when you are having losses? Shrimps normally are good indicators in their behaviour of water quality problems. Transferred fresh filthy filter media is generally your best friend for a new tank.
I don't think your Nitrite levels are high enough to kill fish, assuming an accurate test. My instinct would be to agitate the surface water film with the filter outlet, turn off the CO2, put carbon in the filter and leave the lights on and monitor before gradually reverting to normal.

 

[Bradders]

My personal experience the cycled media does not make instant cycle, but it definitely can help.

I had the same experience recently. I moved very mature media (15 months +) to my new aquarium build, and the cycle still took 4 weeks plus - it was certainly not instant. I never got to the reason why it was not instant - but still interested to understand that!!

I did 90% water change daily and added stability and Sera Nitrite Minus daily, however the daily readings are not going below 0.25ppm for Nitrites. Even after 80% water change I still see 0.025 or higher nitrite levels. Ammonia is 0 since the beginning.

Nitrite at a pH of 7.3 to 7.6 becomes distressing for fish around 2PPM and extremely toxic (death) at around 8PPM. 0.25PPM is nowhere near these levels.

I added some more fishes in it and suddenly I had a massive wave of death in my tank.

I suspect that this would be the cause—something introduced by the new fish which spreads rapidly.

 

[Bradders]

I did 90% water change daily and added stability and Sera Nitrite Minus daily, however the daily readings are not going below 0.25ppm for Nitrites. Even after 80% water change I still see 0.025 or higher nitrite levels. Ammonia is 0 since the beginning.

There are likely to be small amounts of nitrites in your water supply, which is probably why (assuming you can measure that low accurately) you are seeing a 0.025PPM reading. Again, this is not too high to cause problems.

The transition from Amonnia to Nitrate requires bacteria and archea to process. What is your Nitrate reading?

 

[Cornelius]

pH fluctuates between 7.6-7.3

what is the reason that your pH is so high, when using an aqusoil?

 

[Bradders]

what is the reason that your pH is so high, when using an aqusoil?

Let's see what the OP says, but my aqua soil only buffered my hard water to a pH of around 7 for 6 weeks, and now the water is nearly back at tap level (pH 7.7-7.9).

 

[dw1305]

Hi all,
Sorry for your losses, it is never nice when something like this happens.

The tank ran fine for 2 months. I added some more fishes in it and suddenly I had a massive wave of death in my tank. I tested the parameters and saw that the nitrites were off the roof.
I did 90% water change daily and added stability and Sera Nitrite Minus daily, however the daily readings are not going below 0.25ppm for Nitrites. Even after 80% water change I still see 0.025 or higher nitrite levels.

That is really strange. Nitrite (NO2-) is <"reasonably easy to test for">, but I'm not convinced about the accuracy of these readings.

Ammonia is 0 since the beginning.

Particularly if that is <"true as well">.

I'll be honest I'm never going any decisions based on what a NO3- and/or NO2- test tells me. You might be interested in this paper that has come my way via my "day job" <"https://pubs.acs.org/doi/10.1021/acs.jchemed.2c00381">

Because of your tank picture I wonder whether the answer to this is actually nothing to do with TAN ammonia or nitrite? Like the others have suggested?

Now I am wondering why that is it not going down whatsoever. I am missing a few big fishes that I haven't seen since 4 weeks or so since its a heavily planted tank, I am wondering what can be causing this?

Tank is running since 3 months, shouldn't it have cycled by now even with new media even if I hadn't added seeded and matured media in it?
Is it those 3-4 missing fishes that may have died that could be causing a constant nitrites?

They definitely could, but you would expect both some TAN ammonia readings and an increase in plant growth?

Are water changes causing it to not cycle properly?

No, definitely not. The EU is very strict on NO2- levels, because of the risk of "methemoglobinaemia" and nitrate (NO3-) level is irrelevant to this, even if it was near the 50ppm NO3- EU limit.

I run Co2 (1BPS) for 7 hours.

I'm not a CO2 user but I'm going to say that this also shouldn't be a problem, unless the added fish tipped the O2 / CO2 balance far enough that the <"positive feedback loop, ammonia tsunami scenario"> occurred?

cheers Darrel

 

[Bradders]

I'm not a CO2 user but I'm going to say that this also shouldn't be a problem, unless the added fish tipped the O2 / CO2 balance far enough that the <"positive feedback loop, ammonia tsunami scenario"> occurred?

That is a good point, Darrel. @The.WishMaster - when you say massive die out of livestock, can you describe this a little more? How many fish did you add (before the issue)? Also was it a fish every hour, that died or did you wake up and many were dead all at once?

However, on the CO2 point, 1BPS in a 450L aquarium should not be a problem. In fact, I am surprised that BPS is even creating enough CO2 within the aquarium.

 

[Zeus.]

The tank ran fine for 2 months. I added some more fishes in it and suddenly I had a massive wave of death in my tank. I tested the parameters and saw that the nitrites were off the roof.

I am missing a few big fishes that I haven't seen since 4 weeks

Is it those 3-4 missing fishes that may have died that could be causing a constant nitrites?

The most likely cause of the high Nitrite levels IMO

are any of the new fish gasping at the surface mid CO2 period? if not its unlikely to be CO2 related as the DC is green. Some fish IME are more sensitive to the increased CO2 levels