Fishless Cycle - High Nitrites AND High Nitrates for weeks?

H

homerHart

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Apr 6, 2005
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Hi all,

I am new to this game and am going from what I have read on the internet.
I have a 40l tank (v small) and trying to do a fishless cycle. I have added ammonia every day and eventually Nitrites spiked - I then halved the ammount of ammonia (as I have read) and continued - my Nitrites have been 1.6+ppm for about two weeks but my Nitrates have been 100+ppm for about two weeks also? I was lead to believe that once Nitrates had spiked the Nitrites would fall back to 0?
I have done some water changes to try and get the Nitrates down a bit but even after 50% water changes and another 50% the day after they are still 1.6+ppm Nitrites and 100+ppm for Nitrates?
I have tried water changes I have tried not adding ammonia for a day, I have tried adding slightly more ammonia and slightly less and I have also squeezed out the filter sponge (only in a bucket of the water from the tank as it was getting really mucky).
The tank is planted (only a couple of plants)
I have been patient (started the whole process nearly a month ago) I just don't understand why I have high levels of both Nitrites and Nitrates and for so long - I could understand if I had high Nitrites and no Nitrates - I would understand that the Nitrifying bacteria hadn't developed yet, but presumably they have developed and are converting it into Nitrate. But why hasn't the Nitites fallen to 0 after having high Nitrates for weeks now - Help!!! :sad
 
your not supposed to change the water or squeeze out the filter sponge. if you change the water, your taking out the bacteria's food, if you squeeze out the sponge, your gonna kill some of your bacteria

side note: neat smilies

:coffee2: :look: :shark: :hang:
 
I only did the water change and the ' sponge squeeze' after weeks of having high levels of both Nitrites and Nitrates in sheer desperation - thinking that possibly the Nitrates had reached some kind of saturation point and therefore the nitrites could no longer be converted.:confused:
 
water changes to get nitrate to reasonable level

Your instincts on the high nitrate is correct.

You need to continue to change water to get the nitrates to a reasonable level, like 20 to 40ppm. Squeeze out the sponge is good, muck is not good, it smothers the bacteria. You may have a lot of gunk in the gravel also, so do a "surface gravel clean up", just wave the siphon over the top of the gravel to pick up what will float up easily.

I suspect you took the ammonia to such a high level you overwhelmed the tank. Actually you are lucky that you haven't fueled a huge case of green water. Since this is a planted tank, I suggest just changing water to get the tank to reasonable levels, like 10ppm, adding one tiny shot of ammonia to take it to 2ppm and let it go for 24 hours to see if the tank consumes that and if nitrites go to zero.

I think (and I am really reaching here so don't quote me) that the nitrates can back-convert when they get so high.

Do repeated water changes as necessary to get nitrates to 10 ppm, that may require 90% water changes, back to back, as the gravel may be releasing stuff also.

Just for info, it is pretty much unnecessary to fishless-cycle a planted tank, the plants will absorb enough ammonia to allow slow stocking of a tank, typically, though water changes may be needed for awhile also.
 
Nitrates do not get reduced to nitrites under conventional tank conditions -this requires highly specialized conditions and even then do not get released into the water column.

Have products such as "Cycle" been used in this tank? If so, they introduce large quantities of nitrate all by themselves.

A couple of plants are not nearly enough to be considered a planted tank, even in one so small.

The water change suggestions Anonapersona made are good - they do need to be done to get the tank reset to more normal conditions. Have you checked the pH and/or KH? I'd suspect there are water parameter issues and the changes will reset these - you tank may have used up all the KH and pH crashed.
 
Thanks for the replies - I have not used cycle or other similar products.
The gravel 'looks' totally clean - nothing visibly growing on it etc.
As for PH - around 7.7
KH I have no idea as I don't have a test kit.
I will continue with water changes and praying to the bacteria gods :bowing:
 
RTR said:
Nitrates do not get reduced to nitrites under conventional tank conditions -this requires highly specialized conditions and even then do not get released into the water column..
Click to expand...

Thanks for the education, RTR, as always!
 
As suggested - 90% water change done - added ammonia until it registered between 2-5ppm.
Tested Nitrites and Nitrates after water change and still both seem to be high - I guess they must have been extremely high before - I think the trouble is the test kits I have (Nutrafin - liquid ones) particularly the Nitrate and Nitrite tests - the colour chart does not really look anything like the colour of the liquid I end up with - the liquid is far brighter than the paper chart so I have been trying to match the rough tone of the liquid as the actual colour is quite different to the chart - the Ammonia and PH ones are very easy and the liquid matches perfectly with the chart.
I will keep trying - if I get 0 Ammonia and 0 Nitrite in the near future you will all be the first to know. Cheers, Homer :bday:
 
Tested again tonight - still high Nitrates and Nitrites so have done yet another 90% water change - getting very tedious now - don't seem to be getting anywhere. :duh:
 
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