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Nitrogen Cycle - Help Needed


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Hello Everyone.

I feel like my head is about to explode with the amount of research I have been doing, as well as all the conflicting recommendations I keep getting from people who supposedly "know fish keeping".  The only thing that seems to be consistent is when they say my tank test results are "weird".  I apologize as this may be a long post so that I can walk through the entire story and what has been done.

There are 3 sources of fish here in my town that I have received advice from (an aquarium store, a local pet store, and petsmart).  At this point I feel like I know more about the nitrogen cycle than most of them, but am at a loss for what the right next step might be, as I feel I have taken a few missteps already, and am getting conflicting advice from multiple different sources.

The beginning...

I started a 26 gallon tank using Prime and Stability (I have been away from the fish world since I was a kid and was so excited to get into this hobby).  Under the advice of the aquarium store owner, I added 3 Platy.  After running it for a couple weeks, I brought a sample of water to the store to be tested (was waiting on my kit).  It tested with extremely high ammonia.  Was told to do a very small water change and continue using Stability.

Weeks went by and I started testing often.  The ammonia remained high and then the nitrites joined in followed by the nitrates.  I was very confused, as I thought that the cycling would mean that the ammonia would start going down, but it never did.  I tried to get advice from the different locations on what to do, as all 3 remained high.  I started doing small water changes because I was getting mixed advice on whether I should do that while the tank was cycling.


We were a month or more in.  I was constantly testing and doing small water changes trying to help bring the levels down.  I then found out that my tap water had had a spike of ammonia.  I found a better source of water and made more small changes, but it was too late and I lost my fish.

Further mixed advice...

So then I had a tank with no fish that was partially cycled.  I asked around to try to figure out the best course of action...continue running it as is in hopes it would cycle...replace only the water...completely start again...  No one was on the same page.  I decided to continue running it, testing often and doing small water changes to try to bring some of the levels down.  Finally my ammonia levels started to come down.  But nitrites and nitrates remained high together.  So I continued to add Stability and hoped that the tank would cycle.  Then one day I did a quick test and it appeared that it had happened!  I had been told that I needed to get fish back in the tank as soon as possible other wise the good bacteria I was building would start to die, so off to the fish store I went to buy more Platy.

More heartbreak...

They did not even last the night.  Apparently (upon more research), if the nitrites are extremely high, they can actually cause a false negative test.  I had no idea and I was absolutely heartbroken for those poor fish.  I did a 50% water change and retested, and sure enough the nitrites were still sky high.

Now what do I do?

So I continue to run this tank, I continue to do 25-50% water changes (not knowing if that is the right thing to do), and continue to test.  The tests show high nitrites and nitrates and almost no ammonia.  The latest advice today was to do a 100% change as well as clean the filter in the old water; then run it for a couple of days and then get a couple of fish.  I'm not sure what the right answer is.  I know that the bacteria is mostly in the filter media, substrate, and on decorations; so I feel like the water change may not be a bad idea? But would prefer to only do at most 75%.  The tank has been running for around 2 months.

Any knowledgeable advice is very much appreciated. Thank you.

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Hi, welcome to the forum. Super frustrating. I've got 5 cycled tanks but it's still all magic to me. I used Prime and Stability (still do) as tools but I think in the end most of my tanks ended up being "fish in" cycles. Meaning, as you probably know due to research, you cycle the tank while fish are in it.Sadly you've almost done that but lost the fish. Sorry for that 

The easy answer to me is YES!! Any time in your fish keeping experience the Ammonia and Nitrites (Nitrates too at certain levels) are high, do that water change. Sometimes It may require you to do a big one. For example: You have a 10 gallon tank that isn't cycled and you have "fish in". You test often (I'd test daily- if I didn't have time I'd put Prime in every day). Let's say you test it and it shows 1.0 ppm Ammonia. BAD! So you do a 50% water change. Theoretically that may only bring ammonia down by .50. SO use your detoxifier (you mentioned Prime). Wash rinse, repeat every day until you've cycled (and again if you can't do a water change use your Prime)

In my first tank, I made the mistake of adding too many fish at once, that crashed my cycle so essentially I started all over again, but with testing and daily small water changes (and Prime), I got them all through the process alive. 

Your source water will be a problem- but if you have a new source as you mention you shouldn't have an issue trying again. There's still ammonia? I might just do the small water changes, maybe add a little fish food to help and keep with the Stability if you want. Do you have plants?? If not add them now they will help. Did you want "pest" aka bladder snails? Maybe get a few to help start the cycle that way if they did die you might not feel as bad. 

I tried to keep my answer simple and basic. It can be a longer process for some than others so it can be very frustrating. This is the time to focus on the future of the tank, what kinds of scape/plants/fish will ulimately live there. I have an 8 month old tank and have only been able to add 10 fish to it when I can add several more but it takes time and patience. You've kept fish before I'm sure you realize that. There will be others with more answers/options too I'm sure. We all kind of approach these things in our own way. This is why you get different answers- some can be very wrong for you- some are going to workout great.  You can do this, it's just gonna take a minute. 

Oh and I feel you on the research combustion thing. I am always filling my head with fish things. 

Edited by xXInkedPhoenixX
to clarify
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I am a fan of “fishless” cycling. You’ll need to get some ammonia for sure, and maybe some bacteria as a starter. I found my ammonia at Ace Hardware. Check the link below for the bacteria starter. My process is to put 4ppm ammonia in the tank (you’ll need to find a calculator online) and wait until I see the ammonia disappear and nitrite come along, wait some more until nitrites disappear and nitrates come, do a large water change, add 4ppm ammonia and watch it disappear overnight. Then I know my tank is cycled and is ready for fish. Without bacteria supplements this usually takes 2-3 weeks. 

The reason I like this method is because everything is controlled, there’s no variable in the ammonia and no need to constantly test. Also, it builds up the bacteria so it’s very strong.

Good luck. I know it’s frustrating but you’ll get it going eventually.


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