Tank still not cycled?

  • #1
Thank you for letting me join. I have been reading the forums for several months and I have learned a lot. However, I have a question.

I had two 5 gallon tanks set up with a betta in each one for about a month. I decided to buy a 29 gallon tank and took the gravel, water, and both filters and ran them in this new tank. I also added only 4 Black skirt tetras to begin.

I checked all water params daily and never got an ammonia, nitrite or nitrate spike but did have a nasty bacterial bloom that lasted 4 weeks. When I returned to my local LFS, they told me to get a UV sterilizer to clear the bloom and add a few more fish while saying that it is likely that the tank had already cycled but with only 4 fish, the good bacteria kept everything in line. So I added 4 long fin tetras.

The water cleared in 36 hours using the UV sterilizer. Tested params again all still 0. 10 days later added 4 white long fin tetras. Tested water again, all still at 0. 10 days later added 4 head and tail lamp tetras, checked water again, still 0. Added 6 tiny red tetras (sorry can't remember the name they are only maybe a quarter of an inch big) checked water still 0.

So now this tank has been set up about 8 weeks. Now when I have checked the water, I am finally getting some readings. .25 Ammonia, 0 nitrites, 0 nitrates and PH at 7.6. I am running an aqueon 20-40 HOB with an undergravel filter.

Could it be that just now the bio load has increased enough that my tank is finally going to cycle? I have been doing weekly water changes and sweeping the gravel. Should I continue or just wait and keep testing and if Ammonia spikes to .50 then do another water change?

I also only rinse the filter media in old tank water before dumping it after sweeping. I appreciate any help that you could give me.
  • #2
Welcome to the forum!

As bettas have a very low bioload, there may not have been too much bacteria to transfer, but there may have been enough.

Make sure to beat and abuse the #2 nitrate bottle! This reagent includes crystals that can be difficult to get back into suspension. Try testing again and you might find that there is some nitrate in your tank.

Good luck.
  • #3
Welcome to Fishlore!

What type of test kit are you using, liquid or strips? If you are using liquid, there is one bottle that tends to chrystalize in the nitrate test kit. This bottle needs to be banged up pretty good to break up the chrystals in order to get an accurate test. Bang it against the underside of a table, a carpeted floor or even the palm of your hand can work. Continue to bang it for at least one minute.

I think it is likely you have some nitrates to indicate your tank has cycled. The fact that you have a little bit of an ammonia spike right now could be caused from rinsing the filter media too frequently. In a new setup where the beneficial bacteria colony are still trying to establish a good strong colony, even rinsing filter media can contribute to ammonia or nitrite spikes. Only rinse the media when it starts to clog up enough to start to affect your water flow. I usually only have to rinse my filter media in my HOBs once a month. If the filter media is getting too dirty too quickly, it might be an indication you are over feeding. Over feeding can also cause an ammonia or nitrite spike.

A spike can also happen when the stock is increased too rapidly for the bacteria to develop enough to keep up.

If the tank has indeed cycled, and what you are currently experiencing is just a spike, then it will likely be short lived. Try feeding the fish less to keep the ammonia production down until the spike is gone. Decomposing excess food as well as the extra fish waste over feeding can create, can both tax an under developed beneficial bacterial colony.

Keep doing your water changes. A product such as Seachem Prime can help you protect your fish for 24 to 48 hour periods from low level ammonia and/or nitrite readings and should be dosed every 24 to 48 hours until ammonia and nitrite readings are both 0. If your ammonia does increase, daily water changes may be something you will need to do to try to prevent your fish from getting ill.

Ninja'd by catsma. I must have been off in la la land. Didn't think I had been sitting on this post that long.
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  • #4
Thanks. I have been only feeding every other day. I am use the API Master liquid test kit. I have checked it today and ammonia is in between .25 and.50 so I guess I will do a 25% water change. I will bang the out of the nitrate bottle and see what happens. Should I still sweep the gravel or just leave it alone and sweep with the next water change? Thanks for the help.
  • #5
Do gravel vacs once a week with water changes but it would be a good idea to start doing daily water changes to try to keep the toxins low. Look into getting Prime as mentioned before to help protect your fish from the toxins.
  • Thread Starter
  • #6
I have retested and water params are still between .25-.50 ammonia, 0 nitrite and 0 nitrate. I am going to get some Prime tomorrow. I did a water change of 25% yesterday and will do another one tomorrow when I get the Prime. Have had 2 fish die but can't say it is entirely due to the ammonia. One of these fish looked to be pregnant and never did drop the eggs. The other one has rarely come up to eat since I bought it, even though I tried to entice but the other fish always ate the food. So could be a combination of both. IDK. I also have Zeolite in my undergravel filters. Could this be harming the good bacteria? If so then I will remove it. I always used it before in my undergravel filter that I used in the 50 gallon tank that I had and don't remember having any problems. However, that was years ago. But thanks for the help and will let you know how it goes after the prime.
  • #7
Just to make sure you know, Prime won't make ammonia, nitrites or nitrates disappear, but it will turn low levels into a non toxic form that is still usable by the beneficial bacteria and will still show up in your tests. Prime will cause inaccurate test results if you test within the 24 hour period after using it so make sure testing is done before it's use or not until 24 hours have passed after its use.

Zeolite can hinder a cycle. Its properties absorb ammonia through ion exchange. It replaces ammonia ions with sodium ions and locks up the ammonia until it's capacity is incapable of absorbing more. This means the zeolite will prevent beneficial bacteria from developing by robbing it of it's food source. A cycle won't establish if enough zeolite is provided to absorb all of the ammonia. When the zeolite becomes exhausted and starts to allow ammonia to develop, there is very little if any beneficial bacteria available to take care of the ammonia so ammonia and nitrite spikes will happen and then nitrates will develop when a cycle starts to establish. When zeolite becomes exhausted, it requires recharging by soaking it in a brine solution or replacing in order to prevent ammonia from accumulating in the tank. IMO zeolite can be a good product under certain situations for short term use but there really is nothing better than a fully cycled tank to maintain stable levels for the inhabitants.

When using a product like TSS, ammonia has to be available for it's use as soon as the product is added to the tank. This is why if fish aren't already present in the tank when TSS is added, TSS and fish are added at the same time or fish added within 2 hours after using TSS.
  • Thread Starter
  • #8
Evidently my tank had never cycled because I just got Nitrite readings tonight. I knew that prime will change the accurate readings so I have been waiting closer to 48 hours to test. Did a 30% water change and took out the zeolite. So it looks like I am finally on my way. Can't believe it took so long though.

Thanks so much for the information and all of the help. I definitely appreciate it.
  • #9
Don't be surprised to see a rise in ammonia levels since you removed the zeolite. Since you have a nitrite reading, I assume that you had more ammonia than the zeolite could absorb. So you developed a colony of ammonia converting bacteria that was large enough to handle this excess ammonia. But now that the zeolite has been removed, I would think that you will now have more ammonia than you have bacteria to convert it.

But the bacteria multiplies pretty fast, so hopefully any spike you do get will be shorth lived.

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