Help! High nitrites that won't come down!

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FishFinatic77

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Hi! So, I'm In the third week of cycling my 5 gallon betta tank. I already had some old filter media from my other tank, so everything has been going pretty quickly. I got nitrites after about a week, and I got nitrates a week after that. Now, my problem is that my nitrites won't go down. My ammonia will go down to zero in about twelve hours, but my nitrites are consistantly off the charts. When I test for nitrites, the water turns purple before I even shake it up!
I heard that high nitrites can actually stall the cycle, so I did a 30% water change. I tested the water about two hours later, and nothing had changed. I did another 20% water change about 40 minutes ago and tested it again, but my nitrites were just as high.
I just don't understand how it could still be this high, even though I have nitrates. I even tested the water I put in my tank to see if maybe that had nitrites in it. It came up zero. Does anybody know why my nitrites could be this high and how I could lower them? Or do I just have to wait longer? Thanks!
 
Does the tank already have a betta in it or are you doing a fishless cycle with ammonia? If it's the latter, how much ammonia are you adding and how often?
 
There is no betta in it yet. I did not know about cycling for my first tank and many of my fish died, and the ones that did survive really suffered. I never want to put a fish through that again. :sad: Anyway, I am keeping the ammonia at about 2-3ppm. Right now I don't really want to add any ammonia because that would make more nitrites. On the other hand, I don't want to starve my bacteria either. :/
BTW, I just tested my water again and the nitrite levels are still crazy high. :mad:
 
The problem is that you've added too much ammonia. Each 1 ppm ammonia is converted to about 2.6 ppm nitrite, so as the ammonia starts to be converted the nitrite level shoots up. At around 16 ppm, nitrite inhibits the growth of the bacteria. But our test kits only measure up to 5 ppm; no matter how high the nitrite level it will still read 5. The water changes you have done did not bring nitrite down below 5 ppm, so it is quite likely very high.
The nitrate reading will not be accurate as that tester also picks up nitrite.

Can I suggest the first thing you need to do is read this http://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/
Then take as much water as possible out of the tank and refill, making sure the new water is at the same temperature as the old water and that you add dechlorinator. After half an hour, to allow any old water in the substrate to mix in, test for nitrite. If the reading is zero or low down on the scale, add 2 ppm ammonia (a tank for a single betta does not need 3 ppm). But if nitrite is still off the top of the scale, do another full water change, and test after half an hour, and repeat until nitrite is low on the scale.

Once you have added the ammonia, go back to the article in the link. Since you already have ammonia eating bacteria you don't need to start at the beginning. You can ignore the method up to "Continue testing every 3 days (Days 10, 13 etc)."
I suggest you treat the ammonia you have just added as Dose #2 in the method and go forwards from there. Test every other day rather than every day.

You will notice that ammonia is not added very often. It is now known that the ammonia eating bacteria do not starve quickly.
The man who wrote the method explained his research in another thread back in 2013. If you want a long read, see post #8 in this thread http://www.fishforums.net/threads/clarification-on-the-fishless-cycle.420045/
 
Won't taking out that much water mess up the cycle? I just don't want to kill off all the bacteria I've worked so hard to build up. Also, I read the article in the first link, but I can't figure out how ling I'm supposed to wait after I added the second dose of ammonia. Sorry about all the questions, and thanks for your help!
 
The bacteria we want to grow live in the biofilm which is bound to surfaces. There are no filter bacteria free in the water. As long as you remember to add dechlorinator they will be OK.

Once you've got rid of all the nitrite by doing water changes, add 2 ppm ammonia. 2 ppm is plenty for a tank that will have just one betta, the 3 ppm dose in the instructions is for a community tank full of fish.
Miss the next day, and test the day after. Make a note of the ammonia and nitrite reading. Test again 2 days later and make a note. Test again two days later and so on. Whenever you get ammonia at zero and zero again 2 days later add ammonia equal to a third of the first dose - in your case this will be 1/3 of the 2 ppm dose you added earlier. This is to feed the ammonia eaters without adding so much ammonia that it pushes the nitrite up beyond the stall point.
Continue like this, testing every second day till you reach a day where ammonia is less than 0.25 and nitrite is less than 1.0 then add another 2 ppm dose ammonia.
Once you've added this 2 ppm dose, test the next day. If both are zero, the cycle has finished. If one or both are not zero, test every day until ammonia is less than 0.25 and nitrite is less than 1.0 (again) then add 2 ppm ammonia and test next day. If both are zero, the cycle has finished but if one or both are not zero.... Keep repeating till you do get 2 zeros 24 hours after adding 2 ppm ammonia.

You may find that your cycle goes quicker than most as you have probably grown some nitrite eating bacteria, it's just that they have been inhibited by all that nitrite. Once the nitrite is reduced they should start growing again.
 
Ok, I'll try that. Thanks for your help!
 
Ok, so, several water changes later I finally have my nitrites down to 0.25ppm. :yahoo: I can't believe how many nitrites I had in there!
I'm going to add the 2ppm ammonia now, wait two days, and test. If all is good, I'll add the some more ammonia.
This whole nitrite problem was really frustrating because I was so close to finishing my cycle! At least I'm back on track now and hopefully I can get my fish soon. Thanks again for your help!
 
Last edited:
Add the 2 ppm ammonia now. Call this day 0. Test in 2 days (ie day 2). Do nothing. Then test in another 2 days (ie 4th day).
On day 4, it depends on what the readings are on that day and day 2.

There are several possibilities -
1. If on day 4 ammonia is less than 0.25 and nitrite is less than 1.0 then add another 2 ppm ammonia.
2. If ammonia has been zero on day 2 and day 4 but nitrite is still over 1.0 on day 4, add one third of the ammonia that gives 2ppm - that is, enough ammonia to get 0.67 ppm.
3. If ammonia is more than zero on day 2 and day 4 and nitrite is more than 1.0 do nothing and test again on day 6.

You must not add any ammonia until at least day 4, and then the amount you add depends on the results. It could be 2ppm, or 0.67 ppm or none at all. If you add too much ammonia you'll be back to a stalled cycle again.

If on day 4 you are not sure what to do, tell us the test results for days 2 and 4 and we'll tell you what you need to do next.
 
Ok, I'll test tomorrow and see what the results are. Thanks!
 
Ok, I know this is only day 2, but I just tested my water and both ammonia and nitrites were zero. Does this mean my cycle is done? Should I add another 2ppm ammonia and test on Monday?
 
That does sound like it is cycled, or very nearly. I expected it to go very quickly since you already had lots of ammonia eaters and some nitrite eaters. The only question was - were there enough nitrite eaters before the cycle stalled and the answer appears to be yes.

I would add another 2 ppm ammonia to check, and test in 24 hours. If you get double zeros, it's definitely cycled.
 
Ok, I put the 2ppm ammonia in, and I will test tomorrow. If everything looks good, I will get my fish on Tuesday. Fingers crossed! :)
 
Just wanted a to give you an update on the water test I did a little while ago. My ammonia and my nitrites were both at zero! My tank is finally cycled and I can get my betta. Thank you again for all your help!
 

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