QT tank vs Nitrogen Cycle

Hey all! I’m adding a new juvenile pearl gourami to an established tank, so I set up a little QT tank so I can observe for a few weeks. I read about cycling this tank and figured that if I pulled some filter floss from my canister filter on my main (cycled) tank to use as filter media in the QT that it would “insta cycle.”

I just tested (24 hours after setup) and got ammonia 0-.25, nitrites .25, nitrates 5 (filled from main tank so nitrates are not an indication of cycle). I often get 0-.25 ammonia in my main tank- I’m pretty sure it’s a testing artifact- so I’m upset about the nitrites. I did a 50% change and now am reading 0-0-5(ish), but my question is do I make my poor new friend ride out the spikes or just give up and put it in the established tank? Any idea how long the QT will take to stabilize? I’m not a fan of fish-in cycling…

 

I’d probably keep it in the quarantine tank for now - you put it in there for a reason and if you introduce something into your main tank, you will probably regret it.

Can you not move some more cycled media from your existing canister filter into your QT? I’m wondering if there just wasn’t enough bacteria in the floss to fully establish a cycle. Biomedia or sponges would be a better option. For now, continue to keep an eye on parameters and change water when needed (using prime if you have it).

 

I’d probably keep it in the quarantine tank for now - you put it in there for a reason and if you introduce something into your main tank, you will probably regret it.

Can you not move some more cycled media from your existing canister filter into your QT? I’m wondering if there just wasn’t enough bacteria in the floss to fully establish a cycle. Biomedia or sponges would be a better option. For now, continue to keep an eye on parameters and change water when needed (using prime if you have it).

I could. My fear is- how much can I take out before impacting the cycle on my main tank?

 

I could. My fear is- how much can I take out before impacting the cycle on my main tank?

I suppose that would depend on how long the existing tank has been running for and the bioload of it. If it’s a mature established tank then you could remove a reasonable amount of media and not disrupt the cycle.

Another option would be to take some decor from your existing tank and put that in the QT - rocks, wood etc. That should house nitrifying bacteria and help with cycling it.

 

I suppose that would depend on how long the existing tank has been running for and the bioload of it. If it’s a mature established tank then you could remove a reasonable amount of media and not disrupt the cycle.

Another option would be to take some decor from your existing tank and put that in the QT - rocks, wood etc. That should house nitrifying bacteria and help with cycling it.

Fair! My main is a 55g, been up and cycled about three months, moderately stocked about two months. So it’s cycled but I’m not sure about “mature.” I took about 1/6 of the filter media for the QT tank, but it was fine mechanical and not specifically the bioballs, though I assumed the whole filter would be colonized. I’ll monitor today and pull some bioballs if it spikes again. Thanks!!

the QT

 

Hi what is your PH? Nitrite toxicity levels vary depending on the PH. Knowing this will help you determine how often you need to change the water in the QT to keep this little guy safe.

 

Hi what is your PH? Nitrite toxicity levels vary depending on the PH. Knowing this will help you determine how often you need to change the water in the QT to keep this little guy safe.

I did not know that! It’s 6.6 in my main with Co2. Last time I check my tap it was 7.2. I’ll check the QT tank when I get home, but reasonable to say it is in between 6.6-7.2

 

I did not know that! It’s 6.6 in my main with Co2. Last time I check my tap it was 7.2. I’ll check the QT tank when I get home, but reasonable to say it is in between 6.6-7.2

Ok, the higher the ph the better for the nitrite levels. I think that explains also while you’re seeing the nitrites. A different set of nitrifyers grow at a PH of 6.6 then they do in the 7’s. So if the QT tank is the 7’s there probably is a bit of a cycle bump to because you didn’t use enough seeded material but most likely just the wrong type of nitrifyers.

At 6.6 .5 nitrite is alarm and 2.0 is toxic, meaning dead most likely so you’d want to keep them below .5
At 7.2 1.5 is alarm and 6.0 is toxic.

 

Ok, the higher the ph the better for the nitrite levels. I think that explains also while you’re seeing the nitrites. A different set of nitrifyers grow at a PH of 6.6 then they do in the 7’s. So if the QT tank is the 7’s there probably is a bit of a cycle bump to because you didn’t use enough seeded material but most likely just the wrong type of nitrifyers.

At 6.6 .5 nitrite is alarm and 2.0 is toxic, meaning dead most likely so you’d want to keep them below .5
At 7.2 1.5 is alarm and 6.0 is toxic.

Interesting! Is there a chart of this somewhere?

I did a second 50% water change the day after the first and then everything has been testing good since then, so thanks for the help everyone!

 

Yes there is:

 

Yes there is:

Thank you!