Help! Nitrites won’t go down!

Hello everyone! So I’ve been cycling my fluval V 5 gallon tank for the last 11 days and everything has been going pretty quickly. I have been using Fritz ammonia for my fishless cycle and the ammonia phase went pretty fast! I also put some seeding from my other tank as well into the cycling tank which definitely helped cycle it quicker. However, I have reached a point where my nitrites are so high that they seem like they aren’t going down. My nitrates have definitely climbed up each day but my nitrites have stayed the same for atleast 4 days.
Should I do a water change? If so, how much of a water change? My tap water is already dechlorinated so do I have to add prime to the new water? If I do that, will it make the nitrites and ammonia in my tank virtually non-existent? Attached are some pictures from my test this morning. I did add enough ammonia after I tested it to bring the amount up to 0.25 because I know that without ammonia the bacteria will starve.

My aquarium is set to 79 degrees (I would make it hotter but I have plants and there and I don’t want them to die), and I have a large air stone in it as well.
Thank you!

The nitrite test shows the highest colour on the chart so it could be 5 or 15 or 50 ppm there's no way to tell what the level actually is.

How much ammonia did you add, and how often did you add it?
Too much ammonia makes so much nitrite that it stalls the cycle. Since our test kits only measure up to 5 ppm, we cannot know when stall point (~15 ppm) has been reached so we have to keep it below that level by controlling the amount of ammonia added.
If you used the method on here - only adding ammonia when certain targets have been reached - nitrite should be somewhere below stall point. But if you used methods on other sites which say to add ammonia every time it drops to zero, nitrite could be very high.

essjay said:

The nitrite test shows the highest colour on the chart so it could be 5 or 15 or 50 ppm there's no way to tell what the level actually is.

How much ammonia did you add, and how often did you add it?
Too much ammonia makes so much nitrite that it stalls the cycle. Since our test kits only measure up to 5 ppm, we cannot know when stall point (~15 ppm) has been reached so we have to keep it below that level by controlling the amount of ammonia added.
If you used the method on here - only adding ammonia when certain targets have been reached - nitrite should be somewhere below stall point. But if you used methods on other sites which say to add ammonia every time it drops to zero, nitrite could be very high.

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I used the method on this website. I did have to add another “snack dose” (1/3 of normal dose), (although I added a little less, more like 1/4 today) because my ammonia has been at 0 for the last 3 days. This is my second snack dose and I know I’m not supposed to add 2 doses but my nitrites haven’t dropped.

That's good that you didn't use the 'add ammonia every time it drops to zero' methods.

You could try doing a dilution test. It won't be very accurate but it will give you some idea if nitrite is past stall point. Mix 1 part tank water with 2 parts tap water and test it for nitrite. If that gives a reading somewhere on the chart, it's under stall point and it just means waiting. It does take the nitrite eaters longer to grow than the ammonia eaters.
But if the reading is still the highest colour, I would do a water change and continue follopwing the method as if you hadn't done it.

essjay said:

That's good that you didn't use the 'add ammonia every time it drops to zero' methods.

You could try doing a dilution test. It won't be very accurate but it will give you some idea if nitrite is past stall point. Mix 1 part tank water with 2 parts tap water and test it for nitrite. If that gives a reading somewhere on the chart, it's under stall point and it just means waiting. It does take the nitrite eaters longer to grow than the ammonia eaters.
But if the reading is still the highest colour, I would do a water change and continue follopwing the method as if you hadn't done it.

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Thank you so much! For the water change, how much would you recommend I take out? And should I prime my tap water even though it’s pretty clean and doesn’t have any chlorine?

If the dilution test still reads 5 ppm I would change most of it. That would remove most of the nitrite but still leave some to feed the ammonia.

Does your tap water have no chlorine or chloramine at all? That sounds unusual unless you are on well water.



I forgot to ask you - what is the pH in the tank?

My ph is 7.2.
My water is well water
I can’t really tell what the ppm is of the dilution test. I attached a picture of what it looks like.

With that colour, I would change 75 to 80% of the water. That will still leave some nitrite so there is something to feed the bacteria.

The pH is fine, I had just remembered that if it had been below 6 it would have stopped the bacteria growing. But it's well over 6.


With well water there could still be some metals in it and most water conditioners also bind metals. But as you have no fish yet, that's not a problem. Once you have fish, and particularly if you ever want to keep shrimps, I would still use a water conditioner but not Prime. That has a lot in it that you don't need. With no chloramine there is no ammonia in your tap water so you don't need a water conditioner which detoxifies ammonia. Since you are doing a fishless cycle, you don't need to detoxify nitrite as there shouldn't be any once the cycle finishes. Look at API Tap Water Conditioner, that has the least chemicals of any water conditioner.

Thank you so much for the help! I really needed this and I can’t thank you enough. After I take the water out and put new water in, what step should I go to in the cycling method on this website? And how long do you think it will take for my tank to be cycled? I appreciate your help!!

What stage are you at now - ammonia dropped to zero but obviously high nitrite?

I think I would add a 1 ppm dose of ammonia and test in 2 days as for after dose #3 in the method. Then go by the nitrite reading.

It is impossible to say how long it will take as every tank is different. But as a general rule of thumb it takes twice as long for the nitrite eaters to grow as it does for the ammonia eaters.

I am in stage #3. Because I already have nitrates, I don’t know if going back to stage #2 would be helpful. But I can definitely add 1ppm of ammonia and then just wait and see what happens

If nitrite was actually high enough to stall the cycle, the water change should get the cycle back on course and the nitrite eaters should start multiplying again.

Okay, great! Thank you so much!

essjay said:

If nitrite was actually high enough to stall the cycle, the water change should get the cycle back on course and the nitrite eaters should start multiplying again.

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I really appreciate your time and help. Would you maybe know why my nitrites went up so high and maybe how I could prevent this from happening again after I do a water change?

I'm not sure why they went so high since you were following the method on here. The only think I can think of is that perhaps the mature media had a lot of ammonia eaters but not many nitrite eaters and that ammonia was processed much faster than usual; so fast that there was no time for the nitrite eaters to start growing before the ammonia eaters removed all the ammonia. That's just sheer guesswork

Each 1 ppm ammonia is turned into 2.7 ppm nitrite, so keep the ammonia additions well spaced out and only 1 ppm doses. It doesn't take much ammonia to produce 15 ppm nitrite.