looonggg fishless cycle

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Julianna

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Jan 16, 2003
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I recently set up a new 39 gallon fresh water tank. truthfully, not so recently at this point. I've been attempting to cycle the tank without fish. I've been using the method that was recommended here, in which you add enough ammonia to cause the ammonia to spike. when nitrites finally appear, you then halve that amount and continue to add that until the nitrites dissappear. Well my nitrites have been sky high for over 3 weeks. Also, at the very beginning of this cycle, I added a little aqua clear filter on the back with media from my other, well established, tank. Why is this taking soooo looongggg?!? Could I be adding too much ammonia?
Thanks, Julie
 
There has been some back and forth about exactly how the dosing works for fishless.

The original articles say to figure out how much ammonia it takes to reach 5ppm and then dose that amount daily. Some folks (myself among them) thought that you'd wind up with crazily high ammonia levels early on before the ammo-eaters had a chance to get going. So a modified version developed where folks dosed to 5 ppm each day. If the bacteria had barely made a dent in yesterday's dose, why throw in another dose? The first dose could last for several days, but by the end of the cycle the full (or halved) dose is going in daily.

One of the consequences of the early heavy levels is that it suppresses the Nitrite eaters and lets high nitrite levels get built up without anyone to go to work on them, resulting in the never-ending nitrite spike.

If your nitrite levels are high, you might want to try a water change to dilute them back down. The continuing half doses going to your ammo-eaters will produce enough for the nitrite colony, and maybe at friendlier levels. Many folks also recommend a second dose of seed material from an established tank after the ammonia spike has passed, the reasoning being that the initial supply of nitrite eaters starved/were poisoned during the ammonia spkike. Couldn't hurt.

HTH
 
AH HA!!! So I was adding too much ammonia. You are absolutely right....the amt of ammonia I was adding was huge. Adn is still high, I think. So, I should do a water change? How much ?? And then I think I'll cut the amt of ammonia I'm adding in half again. Does that sound good?? Julie
 
No, it doesn't. It's whatever amount brings the ammonia back to 5ppm. Then the next day, at about the same time, it's whatever amount brings it back to 5ppm.

What you should do now, is to change whatever amount of water will bring the ammonia down to 5ppm. Whatever per cent will do that.

If you have a matured tank handy, you might consider the "re-seeding" car guy described.
 
the ammonia in this tank has been returning to 0 by the next day whatever amount I add. That has been the same for over 3 weeks. So I still am unsure of how much water to change. And, your saying that I should add what ever amount it originally took to bring the tank to 5 ppm (since I am always starting at zero) I thought I was supposed to be adding half that amount when the ammonia went to 0 and the nitrites spiked. It was suggested that the whole amount of ammonia would be too much at this point. Yes , no? Julie
 
Do a mighty big water change. A lot of it. Most of it.

Add enough Ammonia to bring the tank up to 3ppm after 10 minutes. The ammonia should work its way around the tank fairly quickly. Use this as your new dosage.

And don't mind that WetFeller, he's been increasingly irascible lately. Quite skeptical too. ;)



HTH
Carpguy

…pedestrian to the soles of my peds
 
Julliana, Thanks for the post. I'm having the same problem. I set up two tanks within days of each other. One tank cycled in two weeks. The other has been "stuck" at the point where ammonia goes to zero every day and the nitrites remain peaked for over two weeks now. I think I overdosed with ammonia early on also (it's hard to tell exactly how high the ammonia level is with the AP ammonia test kit). I'll do a water change tonight in hopes it will cause things to progress quicker.
 
I did the water change on the 4th. The ammonia still disappeared each morning and the nitrites reacted as follows: reduced on the 5th and gone on the 6th and 7th. So it appears to me that the water change was the key this time. I plan to change the water again tonight and get fish tomorrow (Tuesday).

Thanks again to Julianna for posting and to carpguy for the answer.
 
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