Fish-In Cycle Not Working (a.k.a. ready to throw the tank out the window! )

  • #1
We have 2 peppered corys and 3 von rio tetras in a 20 gallon tank (we will get more of each once the cycle is complete, I know they like friends). We set up and got the fish 6 weeks ago last Saturday. I have been managing ammonia with Prime and we did the whole Stability week long cycle and continued to add it about every other day with the 20-25% water changes until last week when I decided it wasn't going to work. I try to keep ammonia at 2 or below. I haven't changed our filter media or done a deep vacuum of the tank (just surface to remove food).

The problem is there has been NO nitrites or nitrates. I even bought a bottle of water to use as a control and nitrates do show up there, so I am shaking the bottles enough.

Does anyone have any advice at this point? Am I doing something wrong? I have looked through the forum and the only thing I can think of doing it emptying nearly all the water and trying Tetra Safe Start with nearly new water. I don't know if that would even work and if I did use TSS, how to I neutralize the chloramine in the tap water? I have read that it isn't compatible with Prime.

I am just so frustrated right now. Everyone seems to have a different opinion from the LFS to those on this and other forums, I am so confused!

  • #2
Do you have enough area (filter medias) for the BB to cling on? What filter are you using? I just use API stress out to dechlorinate water, actually I use a local brand of dechlorinator that I place into the tap water, stir and let it sit for a while. Then I used stress out and stress zyme. Did that when I made a mistake doing fish in cycle, was cycled within a month. But of course there could be several factors that could vary the results. As always no tanks are the same. Also, high ammonia left for too long can also kill the BB that will convert your ammonia to nitrite. I did 40-50% pwc every otherday for almost two weeks just to bring the ammonia down.
  • #3
What's your pH reading in the tank? I have had a cycle stall because my pH bottomed out when I wasn't watching.
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  • #4
The filter is a aqueon QuietFlow 10 for 20 gallon tanks. About 2 weeks ago I cut the carbon out of the filter cartridge and left the filiment in. According to the manufacturer, the bio filter is a plastic holster which holds the replaceable cartridge. The ph is around 7.4, so I don't think that is it.
  • #5
Why did you cut out the carbon? That would not inhibit the cycle and may help with ammonia control.

A lot of people recommend tetra safe start for fish in cycles. There are some good posts on this site about using that. I have never attempted a fish in cycle always opting for fishless so I do not have personal success techniques to share. I can tell you that my most successful and fastest fishless cycles was due to having seed material from established tanks like a filter cartridge, bio wheel (as long as there are two to leave one), gravel in a footy hose placed at the filter intake, bio balls, or other biological media. TSS may provide that same effect if you do not have access to an established tank for beneficial bacteria. Read up on it to see if that may speed things along for you.

Another note. I would personally add more filtration. I always use a filter recommended for twice the size of the tank paying attention to the gallons per hour it will turn. My rule of thumb is a minimum of 10x the tank size so you would need 200+gph. This would also provide more surface area for buildup of bb. If you add another filter, you would want to keep the current one going as well at least for a couple months to retain the cycle once it is established.

Patience is key when establishing a cycle. It makes it more stressful with fish already involved so I get your frustration. Dosing prime will deactivate the ammonia making it safer for your fish. Again, I do not have experience using it with TSS so research those posts and come back with questions. There are some folks on this forum with expertise in this area.

Good luck and hang in there!
  • #6
Another note about checking all your levels.
PH – a low PH can cause problems with the fishless cycle. Below PH 6 the bacteria can become much less active and may even stop processing toxins and die off.
KH – low carbonate hardness can also cause problems. Carbonates are used up during the nitrification process so if KH falls too far there won’t be enough carbonates in the water for the nitrification process to work.
Be sure you have good test kits to monitor and keep these level drops from sabotaging your cycle process.
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  • #7
This is what I have decided to do. I just did a 50% water change and treated the tap water with Prime. I have ammonia down to around .5, under the max of 2-3.5 recommended by the manufacturer for TSS to work.

Tomorrow night, about 30 hours after adding Prime (over the recommended 24) I will add TSS, enough for a 40 gallon tank as recommended by another user, and test after 48 hours. I hope to not have to do water changes for at least a week. I will update for future users in a week or two.
  • #8
Welcome to the forum and glad you joined us. First take a deep breath, then count to 10. I did three fish in cycles with TSS. Do not throw out you water and start again. Prime dechlorinates and also removes the chloramine and most of us use it for water changes. It is okay to add TSS to the tank 24 hours after adding the prime. . Get an appropriate size bottle of TSS Start UP or TSS plus for your 20 gallon tank and dump the whole thing in your tank, every last drop. Then do nothing except feed your fish for 2 weeks. Do not do water changes or test your water as it will cause readings that if you treat you will mess up your cycle. There is another TSS bottle that says monthly on the front and that is the wrong one. All the two bottles are is the good bacteria so you can't put too much in. Where you have gone as far as you have in your cycle than it might be enough to complete your cycle in a few days. In your case you could test but don't treat. If you need to add more water to the tank after a few days or until the cycle is complete than just add 2 drops of prime per gallon of water. Keep us posted on your progress, it will happen , honest. Alison
  • #9
Hi, welcome to fishlore

Sounds like maybe you got a bad bottle of Stability. A regular fish-in cycle without a bacterial additive will take anywhere from 4-12 weeks. With a bacteria it should work in a couple weeks (generally).

I think trying TSS now is a smart move as we don't know what happened with the stability though usually its a great product.
  • Thread Starter
  • #10
Did a 50% water change and got ammonia down to .5. Waited 24 hours for the Prime to clear and added TSS, ammonia was .5-1 at that time and hasn't risen. That was 4 days ago and I got 5ppm Nitrates last night! Yay, looks like the nitrites were skipped like many say. Just so happy it looks like the TSS is actually working!

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