Nitrites rising after they were dropping during fishless cycle

[byanymeans]

I am in week 6 of my fishless cycle and everything was progressing well, albeit slowly, until the last two days. For the last 10 days my ammonia levels have been dropping to zero after being at 4.0-5.0 ppm (dosing ammonia daily to bring back to 4.0-5.0). My nitrites began dropping about 6 days ago and got as low as .25ppm, however the last two days it has gone up to between 1.0-2.0, while the ammonia still drops to zero. My PH has dropped as well, but is currently at 7.4. Any advice would be appreciated. Here are my current parameters:

72 gallon bowfront, temp. 77.2, PH 7.4 (would like it higher- planning on african cichlids), ammonia 0, nitrites 1.0-2.0).

 

[Kasakato]

Nitrate level?

 

[rohnds]

What is you nitrate NO3 reading?
How much did the pH level drop?

Are you sure that it isn't your NO3 levels that are rising and not your nitrites NO2 levels?

Rohn

 

[byanymeans]

Yes, I am sure it is the nitrites and not the nitrates. I am checking the nitrate level now and will post the results. The PH dropped from 8.4 to 7.4. I have not checked it daily so I don't know if its a gradual decrease or animmediate one (4/18/05 - 8.4; 4/24/05 - 7.4).

 

[byanymeans]

Parameters as of 10:30 am today: ammonia 0ppm (4.0 ppm last night); nitrites 2.0 ppm; nitrates 5.0-10 ppm (thought they would be higher);and PH 7.4 (comes out of the tap at 7.8-8.0).

As stated earlier, nitrites were dropping a couple of days ago (to as low as 0.25 ppm), however they started rising again. Any ideas as to why this is happening. I am in the 43rd day of the cycle. :help:

 

[OrionGirl]

The bacteria colony that is creating the nitrites is now full sized, while the colony that consumes the nitrites (creating nitrates) is not. Did nitrites previously spike? I don't this is anything to worry about--the nitrite consumers can be slowest to develop, and is one reason many people reduce their ammonia additions.

 

[byanymeans]

Should I reduce my ammonia dosage? If so, how much? I originally started the cycle six weeks ago with an initial dosage of 15 ml of ammonia which brought the levels to 4.0 - 5.0ppm. I then didn't add anything until the level dropped below that number. I now add 7.5 ml daily which brings it up to 4.0ppm and it usually drops to zero within approximately 12 hours. Should I continue this regimen? As stated before, my nitrites dropped to as low as .25 ppm a couple of days ago, but now they are back up to 2.0.

Also, my nitrites spiked several weeks ago.

 

[Kasakato]

Ya. Kepp adding enought ammoina every day to get the level to 3ppm. Also keep testing. When you see that the 3ppm of ammoina has turned into nitrite, and then nitrate all in less than 24h you are done your cycle. This can take takes up to 8 weeks, so hang on. (Only 2 weeks to go)

 

[ariston]

I'm at about day 30 of my fishless cycle, and my nitrites go up and down a little, too, from about 0.25 to 0.75. But I've occasionally messed around with the gravel (adding or removing decorations, etc.), and I've definitely noticed a correlation with that. For example, fter totally re-arranging the tank, my nitrites spiked a little. Then I skipped a day of adding ammonia to make up for it, and then my nitrites dropped to their lowest, at 0.25. Now I'm back to constant daily dosing of ammonia (to 1 ppm), and my nitrites seem to be slowly falling again. (Once I get to 0 nitrites within 24 hours of a 1 ppm ammonia dose, I'll increase the daily ammonia dose to 2 or 3 times that, and then when the nitrites are again going to zero within 24 hours, I'll consider the tank cycled.)

 

[ariston]

I originally started the cycle six weeks ago with an initial dosage of 15 ml of ammonia which brought the levels to 4.0 - 5.0ppm. I then didn't add anything until the level dropped below that number. I now add 7.5 ml daily which brings it up to 4.0ppm

Hm, I just noticed these numbers. They don't seem right, do they? If 15 ml brought you to 4-5 ppm initially, then 7.5 ml should bring you to something substantially less than 4 ppm.

Still, if you've been keeping the dose constant at 7.5 ml for a while, the only reason I can think that your nitrites would have started going up again is if there was some interference with the bacteria colony (large temp or pH change, filter media change, gravel disturbance, etc.).