• Get the NEW AquariaCentral iOS app --> // Android version will be out soon!


AC Members
Dec 8, 2020
Do you have fish yet? It sounded like not...but now I'm not sure.
I’m wondering that too, if there’s no fish, no ammonia in the tap, and no cleaning products used in cleaning the tank, unless the filters are packed full of detritus, I’m at a loss as to where the ammonia could be coming from. My only conclusion at that point would be a faulty test


Mar 29, 2005
Have someone else test your water, and use a different test kit.

Maybe have somewhere that can do the API Aquaspin tests, or invest in a Seachem ammonia alert.

Either which way, if you do a 100% water change right now you should have 0 ammonia. If it gets too high, you are unlikely to cycle any which way.
  • Like
Reactions: FishAddict74


AC Members
Jun 28, 2006
SF Bay area, CA
So where is the ammonia coming from as FA74 asked? Did you dose it maybe too high? Above about 3 ppm or 4 the cycle stalls. We need actual numbers or at least a range...for all your parameters. You might have a shop test your water, something's wrong. Write down what they tell you, not just OK but real numbers please.
  • Like
Reactions: FishAddict74


AC Members
Mar 21, 2020
Camera Used
My iPad
I am sorry, but this is simply not true. I know the chemistry involved. However, there is also a limit to how much ammonium (NH4) fish can handle.

It is also not true that nitrification stops in acid water. What happens is the bacteria involved will have receptors for NH4 instead of or in addition to those for NH3. Also, plants use ammonium and nitrifying bacteria mostly use ammonia (NH3). However, nature is pretty good at how it works and that is why some bacteria are able to process ammonium. Bacteria process NH4 less efficiently than NH3.

I have come to believe that almost no fish keeper should ever do a fish in cycle. Most who believe they know what they are doing in this respect actually do not. They end up harming or killing fish. While I wrote two articles on how to deal with a fish in cycle gone wild, I will no longer help people who use this method. I will refer them to my artciles. If you do not know the answers or how to calculate the answers to the following, you should probably not be doing a fish in cycle.

1. How do you know how much of a total ammonia reading is in each form- NH3 and NH4.
2. At what level does NH3 start to become toxic to most fish?
3. How much ammonium can fish live with, and for how long?
4. What is the difference between the nitrogen scale and the total ion scale.
5. How does nitrite harm/kill fish and how can this be prevented without doing any water changes?
8. How does one do diluted testing and when is this needed and why?

I am willing to work with anybody to help them complete a fishless cycle. I have done this a number of times over the years and it always works. Without any help from seeding a tank or having live plants, it will take 4-6 weeks to fully cycle a tank without using any fish. How long actually depends on how much bacteria one has at the outset. The answer is, whatever comes in via one's tap. This is highly variable and cannot be determined in advance. And this fact accounts for the difference between 4 and 6 weeks. It also assumes one makes no serious mistakes along the way.

My favorite thing in temrs of helping with cycles was a couple of years ago when my fish club worked with a local 4H group. We worked with a dozen kids in the 10-12 year old range set up their first tanks. Their parents were also involved. This was a summer project that had only a few months to run. My contribution was to provide each 10 gal. tank with a fullly cycled foam filter and mulm. I did this in about 2.5 weeks :) Imagine if these newbies had needed to cycle/establish their own tanks. The club supplied all they needed- tanks, lids, lights, filters, air pumps, thermometers, substrate, decor, dechlor live plants, fish etc. We did teach them about the cycle, but did it for them this time.
I have always done a fish in cycle. But that is only i never knew about the cycle and could no get any hold of any ammonia source and especially already seeded tank to put my fish in. My fish were my ammonia source. I cycled my 125L tank with fish in, did every day water changes and my ammonia was always 0.5-0.25, same with nitrite.