Can you cycle nitrites and stil have high ammonia?

[Eldan]

I have a 6 gallon tank with 2 zebra danios that I've been trying to cycle for 8 weeks. It's got an integrated charcoal filter and a biowheel.

It seemed like it was working. At around day 38 nitrites peaked, then they went to zero. But ammonia did not go to zero. In fact, it's been rising and rising, as the attached chart shows.

I just did my first nitrate test and got 10 ppm. I wish now that I had tracked nitrates all along. I did three 25% water changes since starting the tank.

Could the zero nitrites mean that I have established a nitrifying colony? Or could the zero nitrites plus high ammonia mean I somehow lost all the nitrosifying bacteria? What gives?

Is it possible that I have a healthy amount of nitrosifying bacteria but the ammonia load is just too high for them? What would you do next?

 

[jsoong]

If the ammonia is sky high (assuming that the tests are accurate), it is quite possible that you have lost the biofilter completely. Without bacteria to convert NH3 to NO2, you would see a drop in the nitrites, mimicking its conversion to nitrates.

Super high ammonia (around 8 ) can kill off the bacteria, maybe something like that has happened. Or perhaps the bacteria got killed with a pwc without dechlorinator, or some sopa or something got into the tank? I would think you should be doing a 75% pwc to get that ammonia down to something reasonable & take it from there.

That nitrate might be left-over from when you still have a cycle. I would test the tap water for nitrates (often there is some in water, esp. in rural areas) to see where you are starting from. See what happens after the big pwc. If the nitrates are increasing in spite of persistent high ammonia, I might suspect an error in the ammonia test. But for now, you are safer to assume that you have lost the biofilter somehow.

 

[Eldan]

Thanks. I really wonder what it was. It couldn't be soap. I do have a dedicated pail. I'm using Aquasafe for Goldfish. It was the only one I could find at the time, and the label says it's for all freshwater fish... The tests are the API master kit.

The only other weird thing is I have pretty hard water. It tested pH 8.1 from the tap. Also I'm keeping the temperature at 73 F because I'm told zebras like it cool. But am I hampering the development of bacteria at that temp?

I did 25% pwc today. I'll do a 50% change tomorrow, and I'll test the tap water for a control.

 

[Solarris]

This sounds kind of like what's been happening with my tank this weekend. I thought my cycle was almost over, my ammonia had been holding at 0.25ppm for a couple weeks but I was hoping it would drop to 0 soon, and my nitrites had dropped to 0.1ppm. I tested my water on Thursday however to find my ammonia was at 0.5ppm and nitrites were still 0.1 then when I tested yesterday my ammonia was closer to 1.0 and my nitrites had dropped to 0.05ppm. I haven't run any tests today. I'm not sure what is causing this. I haven't performed any pwc's in the past several days and, like you said, I'm using a dedicated bucket so there's no worry of soap contaminating it plus I'm always extra careful to add the dechlorinator before I add the water to the tank.

 

[Blueiz]

Have you increased feeding, fed anything different? Since the biofilter isn't 100 percent established it can be really sensitive to these things.

 

[jsoong]

The hard water shouldn't be a problem with cycling. However, ammonia is more toxic in hard water, so with your level of 7+, I would expect to see some bad effects on the fish. if the fish is looking fine, I would lean more towards a test error. Perhaps you should test ammonia in the tap as well, just to make sure the kit isn't off.

Zebra danios should be fine in water anywhere in the 70's. It would speed up the cycle if you have the temp in the high 70's, but your temp should not give weird readings like yours.

Overfeeding, etc. might give you a mini-cycle. However, I would expect a rise in NO2 as well as NH3, so that can't explain the findings.

Solarris, the difference of 0.5 & 1.0 in a home test is not significant, and can easily be due to test error. <Personally, I can be easily one or 2 squares off when matching the color card depending on light, etc ..... luckily, I can still tell zero, which is all I needed to know.> I won't sweat the results you are getting just yet. Give it a few days & see what happens.

 

[Eldan]

Blueiz, feeding has been a constant pinch of Tetramin flakes, once a day. I'm sure we overfed occasionally, but we sure tried not to.

Did a 50% water change today, and tested the Aquasafe-treated tap water. Ammonia was 0 ppm, and Nitrate was 10 ppm. So it looks like I never really got to the nitrifying part of the cycle before it crashed, but there is no apparent error in my ammonia test.

I'm obviously not the most experienced observer of zebra behavior, but they never seemed to be distressed.

What a bummer that I have to start over! I was following a school of thought that you shouldn't do as many water changes while cycling because you'll prolong it, but I think I'm going to switch it up and start frequent water changes as soon as I see nitrites. Thoughts?

 

[jsoong]

I am of the school of keeping the ammonia & nitrites low when doing fishy cycling. I think it is more humane for the fish, even tho it might take longer for the cycle to be established.

You might still have some bacteria left in the tank, so hopefully the second go round won't take as long. this fish keeping thing sure can try one's patience sometimes.