Cycle Question?

[electropunk06]

hi i am currently fishless cycling a 90L and would like to know what i am looking for.
the ammonia is taking about 24 hours to drop from 8+ppm to nothing is this about right?
thanks

 

[toshapetriji]

You are looking for 5ppm of ammonia to drop to zero in 12 hours
In addition at the 12 hour point you should have a zero reading for Nitrite also.

Once you can maintain this for 1 week you can consider the tank cycled.

I would say you are well on your way but reduce that ammonia dosing down to 5ppm.

 

[waterdrop]

Agree, dosing at 8+ppm concentration encourages the wrong species of autotrophic bacteria to populate the biofilter media surfaces. A short period of elevated dosing won't cause much harm though. Has it been too high for long?

Usually the ammonia first begins dropping all the way to zero ppm in 24 hours at roughly the same time that nitrite(NO2) begins to appear. This is followed by the 2nd phase of fishless cycling where the nitrite(NO2) results are above the maximum measurable level of the nitrite test, which can go on for weeks.

Finally, the nitrite(NO2) abruptly drops to zero ppm within 24 hours and begins doing this each day. This marks the 3rd phase (post "nitrite spike") of the fishless cycle and the object becomes to hope that nitrite(NO2) can drop to zero ppm within 12 hours after dosing, rather than longer than 12 hours. Dosing should always occur on roughly the same hour of the day and only once per 24 hour period. In the 3rd phase however, an extra test set is done at 12 hours.

Once both nitrite(NO2) (and ammonia of course) drops to zero ppm within 12 hours, you are ready to start your "qualifying week," which just means you watch that it performs the same feat consistently for a week before declaring the fishless cycle at its end.

~~waterdrop~~

 

[electropunk06]

it was only 8 ppm for two nights.
i have now dropped it to 5 ppm which i top up every day.
i have only checked after 12 hours once and it was at 0.25 ppm.
my no3 is at 80ppm at the min which seems a bit high what should it be at?
thanks for the replays,
lloyd

 

[OldMan47]

The nitrate is immaterial until you see the nitrites moving down to zero after the ammonia processors have created those nitrites. How high are your nitrites right now?

 

[waterdrop]

Agree with the question: How high are your nitrites(NO2)?

Also, ammonia is only topped up once you test and the concentration of ammonia in your tank water has dropped all the way down to zero ppm or a trace that is very close to it. Usually when you first start fishless cycling (depending on how many ammonia oxidizing bacteria your tank has happened to start with) it will take a number of days or even weeks before ammonia drops from the dosed 5ppm down to zero ppm for the first time.

~~waterdrop~~

 

[electropunk06]

just done another test at 11:45 after adding amonia up to 5ppm at 7:10 this morning
ammonia: 0.5 ppm
nitrite NO2: 0.25 ppm
nitrate NO3: 1-5ppm
so it looks like it is nearly done.
thanks for the replys

 

[electropunk06]

just done another test after 7 hours after upping to 5ppm:
ammonia: 2 ppm
nitrite NO2: 0.25 ppm

 

[waterdrop]

Yes, looks like you are in "Phase 3" (out of 3) (the "after nitrite spike" stage) of the fishless cycle. It sounds like you understand what you are looking for: you want to see both the ammonia and the nitrite(NO2) drop all the way to zero ppm, within 12 hours after dosing to 5ppm, so that you can start your "qualification week." During the qualification week you just want to confirm that the filter can repeat the performance for a week. In our experience this helps confirm that the filter will not "mini-cycle" on you after you add fish. Some filters will fool you by reaching zeros but still spiking unexpectedly after fish - this is what the qualifying week is all about.

~~waterdrop~~

 

[electropunk06]

i added 5ppm of amonia last night at 19:15, this morning at 7:15 ammonia was at zero and nitrite was at 5ppm and then at 16:45 when i got in from work it was still at 5ppm. i have just tested now it has dropped very slightly but is still very high. it seemed to drop alot quicker than this at the weekend. i added some substrate to the tank, could this have affected the bacteria? or is this just a coincidence?
Lloyd

 

[waterdrop]

Maybe I spoke too soon, maybe you are just at the end of the first stage and heading in to the nitrite spike. How many days total have there been since you did your very first dose of ammonia for fishless cycling?

~~waterdrop~~

 

[electropunk06]

Maybe I spoke too soon, maybe you are just at the end of the first stage and heading in to the nitrite spike. How many days total have there been since you did your very first dose of ammonia for fishless cycling?

~~waterdrop~~

about 5 weeks, but i didn't have a test kit for the first 3 weeks so i ''used the force'' and added a little amonia every week. but since ive been testing the NO2 has been falling faster than this.
thanks
Lloyd

 

[Katch]

More data needed to really qualify what is happening. Keep posting your results each day only adding ammonia at your specific add hour each day. Bring it to 5ppm and then test 12h and 24h later.

If ammonia and nitrite are zero after 24h its just a case of sticking with it till you get zeros at 12 hours. Don't be alarmed by results after 5 or 6 hours as a lot can happen in those extra 6 hours. Remember Nitrite cannot process at all whilst ammonia is present. So as we cycle a tank the ammonia has to process to zero before the nitrite starts to move.

I'd be interested to know your temperature and pH as if these are not optimal it could cause your cycle to stall (which may explain the setback). You want the temperature at 29 degress C and pH around 8.4 for optimal bacteria growth. Also your Nitrates can cause the cycle to stall if they get very high. As WD has said, when we get frustrated we perform a w/c - it does no harm, makes us feel better and is usually beneficial to whatever we are trying to achieve. If all else is fine and you still have little progress in the next few days go for a near 100% water change making sure you add plenty of water conditioner.

Keep us posted and good luck.

 

[waterdrop]

Katch wrote:
"Remember Nitrite cannot process at all whilst ammonia is present. So as we cycle a tank the ammonia has to process to zero before the nitrite starts to move."

I don't believe this is correct. The Nitrospira spp. should be perfectly capable of processing nitrite into nitrate despite the presence of ammonia. The Nitrosomonas and Nitrospira are each independently "doing their own thing" on a continuous basis.

If you have an information source and I'm missing something please let me know.

~~waterdrop~~

 

[electropunk06]

hi thanks for the help guys,
i tested this morning and nitrite was at 0ppm so i added more ammonia.
now after 9 hours the readings are
ammonia: 1ppm
natrite: 5+ppm
nitrate: 10-20ppm
ph: 6.6-6.8
temp: has been at 30C but i must have changed it when i was putting the substrate in, it has been 20C for 3 days, could this be why the nitrite has slowed down?
Lloyd