Fishless Cycle in a Rut?

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aklaum

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Dec 31, 2005
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Hello all,

This is my first post. I am cycling a new 20 gallon tank with the fishless cycling/household ammonia method. I have gone with the general theory of taking the ammonia up to 5ppm and letting it get back to 0ppm and then adding enough ammonia to get it back to 5ppm. It took about 2 weeks for the ammonia to move at all. Finally one day it started to go down.

Once it hit 0ppm I added more ammonia and took it back to 5ppm. 10 hours later it was back to 0ppm. Excellent! I thought. I tested for nitrites. Off the chart. Wonderful! I thought. I did this cycle two more times and each time it went from 5ppm to 0 in about 10 hours. Go bacteria go! I thought.

Then I went for another cycle. I took it back up to 5ppm expecting the same kind of turnaround. It is now 4 days later and it has just now gotten back to 1ppm. Serious reduction in ammonia consumption speed. I tested for nitrites again. Still just off the scale of my test kit but far less hot pink than before. Maybe 11ppm?

Nothing has changed in the tank. I have it set at 85 degrees and I have a temporary powerhead installed oxygenating the heck out of the water.

I'm not sure what this means or where to go from here. What could be happening?

Also if I do get through this 5ppm ammonia cycle, how much can I stock the tank when it is complete? People have said that one of the benefits of fishless cycling is that you can fully stock the tank once the cycle is complete. Would this be true in this case or have I only simulated a few zebra danios and should only add fish slowly once the cycle is complete.

Also, just today I noticed some brown growth on the fake plants. This is occurring mainly around the output of the powerhead. Is this a brown algae? Is it possible to over oxygenate a tank? This is a 270gph powerhead running at full blast with the air intake at maximum, so lots of flow, lots of air, lots of bubbles.

Any help would be appreciated.
 

Diego L.

peacefull fish
Dec 20, 2005
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umm....I'm not sure but I believe nitrites are bad...so off the charts isnt good..
 

mishi8

Go fly a kite!
Jan 13, 2005
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Alberta
If your nitrites are off the charts, then it's possible that the high nitrite level has stalled your cycle, and is affecting the bacteria that consume ammonia, as well as the bacteria that consume nitrite. I recommend you do a large water change (80-90%) to bring the nitrites back down to a much lower (and readable!) level. Do more than one water change if needed. After that, add more ammonia, BUT only half of your original dose of ammonia (once you start seeing nitrites during a fishless cycle, you need to halve the ammonia dose.) Hopefully this will bring the cycle back in line. BTW, have you been checking your KH and pH at all?

The algae you are seeing is likely due to the high ammonia levels.
 

aklaum

AC Members
Dec 31, 2005
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Thanks for your quick replies!

I just did a 5 in 1 Quick Strip test and got the following:

Nitrate: 80 ppm
Nitrite: > 10 ppm
Hardness: 75
Alkalinity: 0
pH: 6.2

The Nitrite reading is just a little pinker than the highest shown reading in the test kit. I thought a high Nitrite spike was normal with fishless cycling?

I'm guessing from those particular Alkalinity and pH readings that they have "collapsed" as you said RTR?

Will the large water change solve all ills going on right now? If so I will do it tonight.
 
Last edited:

hurricanejedi

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Apr 4, 2005
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I'm just learning about fishless cycling too. The 5ppm prepares you for the full bioload of your tank. So whatever would comfortably fit in your tank you should stock immediatley. I would post a list of the fish you would like on here for people to give you feedback on whether its too much or not.

The nitrates would indicate your nitrites are being converted to nitrates meaning your slower growing bacteria colony are actually in place. So maybe the water changes will help but it seems if you get back to the 10 hour thing again you should be really close...
 

daveedka

Purple is the color of Royalty
Jan 30, 2004
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RTR hit the nail on the head in my opinion. pH 6.2 = KH really low if not 0. The bacteria need and consume carbonate. If Carbonate depletes, the pH crashes and the bacteria stall or die depending on severity and length of time for the crash. Depending on what your tap Kh is a water change would probably be the easiest thing to do. You can also add baking soda (carefully) to increase carbonate. For lots of information, guidelines and help try this article:

http://www.aquariacentral.com/forums/showthread.php?t=64301

Dave
 

daveedka

Purple is the color of Royalty
Jan 30, 2004
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Columbus, ohio
Also you should not have your tank light on during a fishless cycle, and therefore should have no algae at all. Ammonia+ light= algae.

And if your tank can consume 5 ppm ammonia and the nitrite it produces in 24 hours or less it will have enough bacteria to handle a full stock load at once.
dave
 

aklaum

AC Members
Dec 31, 2005
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Thanks again for all of the quick replys.

I did a 90% water change just now. I am going to wait a little bit then post the results of another 5 in 1 strip test.

I am assuming at this point that the bacteria that are left will now have nothing (or very little) to eat since I did such a large water change. So it makes sense to me that at this point I would add more ammonia to give them a food source again.

So the question at this point in the madness is:

5ppm or 2ppm?

(as in how much ammonia should I add)

Also how often should I check the pH, KH during the rest of this cycle to make sure this doesn't happen again?
 
Last edited:

aklaum

AC Members
Dec 31, 2005
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Ok, after an hour of water circulation I did another 5 in 1 test, results were:

Nitrate: 20 ppm
Nitrite: 3 ppm
Hardness: 75
Alkalinity: 0
pH: 6.8

Not much of a difference in KH, pH after a 90% water change. I added 2 teaspoons of baking soda. After letting that circulate for a while I got the folowing:

Nitrate: 20 ppm
Nitrite: 3 ppm
Hardness: 75
Alkalinity: 120 ppm
pH: 7.2

To get the whole mess going again I added enough ammonia to hit 5ppm and am calling it a night. Geez I was stressing out and we are only talking bacteria here, not even fish yet. The main reason for stress is that this tank was a Christmas gift for my 7 year old son. We have been cycling since Christmas day. He has been wonderfully patient. I sat him down and explained the nitrogen cycle which he grasped, but the thought of starting this whole process all over again makes me want to retch.
 
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