Fishless Cycle Lagg & Stocking Question

[mark4785]

Hi,

I've been conducting a fishless cycle (add and wait method) on a 60Ltr quarantine tank since the 10th of August this year and I'm still having issues trying to get the nitrite level to be converted every 12 hours resulting in 0 ppm of nitrite.

By the 23rd of August, my ammonia level was 0ppm every 24 hours and by the 9th of September the level was 0 ppm every 12 hours.
As for my nitrite readings, they have been varied since the 10th of August through to 20th of September. Thereafter, the level was a consistent 5 ppm+.

I think the reason for the nitrite level being varied from 10/8/10 to 20/9/10 is due to the fact that during this period I had an additional established filter sponge installed in the tank (taken from pond filter) as I need to house a fish in there for a short period. On the 20/9/10 I removed the established pond sponge and only the uncycled media remained in there.

Would what I did, as described in paragraph above, cause issues with fishless cycling an aquarium for any reason?

 

[hillmar77]

And what is your nitrate readings at the moment? Using the establish media should have given you some beneficial bacteria to work with.

 

[mark4785]

And what is your nitrate readings at the moment? Using the establish media should have given you some beneficial bacteria to work with.

I haven't tested for nitrate yet. I should imagine the nitrate level is 160ppm+ as I've never done a water change in the tank during the fishless cycle.

 

[waterdrop]

If your nitrate level has been that high it will have been inhibiting N-Bac growth and more importanly there's a good chance the nitric acid component (when nitrate dissociates in water, about 7% of it is in the nitric acid state) has crashed your pH (if your KH is low) and stopped all the cycling activity. Have you monitored pH periodically?

~~waterdrop~~

 

[mark4785]

If your nitrate level has been that high it will have been inhibiting N-Bac growth and more importanly there's a good chance the nitric acid component (when nitrate dissociates in water, about 7% of it is in the nitric acid state) has crashed your pH (if your KH is low) and stopped all the cycling activity. Have you monitored pH periodically?

~~waterdrop~~

Yes, I monitor the Ammonia, nitrite and PH daily. The lowest the PH has gone is 7.8 which I always respond to by putting some bicarbonate of soda into the water.

I did a 60% water change yesterday and I'm continuing the cycle with water that will definitely have a lower amount of nitrate in it.

 

[waterdrop]

Its hard to predict what the period with the pond sponge in may have done to the overall progress of your fishless cycle. As mentioned, it will have provided the opportunity for some autotrophic colony cells to migrate from the mature sponge to some of your immature sponge. On the other hand, the mature sponge may have simply multiplied a number of colonies close by, still on the same mature sponge, in response to the excess ammonia being provided by the fishless cycling process. Then, when removed, the immature sponge may still have been at nearly the same early stage, having not moved along as much as expected.

~~waterdrop~~

 

[mark4785]

I've done 2 water changes. For the first I replaced 50% of the water. I tested the nitrate level afterwards and it was 160ppm+!

I conducted another water change, this time taking 90% out. I re-tested for nitrate and the level was about 80ppm.

I've resumed cycling the aquarium but now an ammonia spike of 1.0 ppm has occurred and the nitrite has stalled at 5 ppm.

I can understand the nitrite level stalling has it is quite difficult to get it to zero during cycling, whereas ammonia will reduce to consistently zero within a week or two. Any explanations as to why the ammonia level has risen?

note: I dechrlorinated all of the replacement water and I've not touched any of the filter media.

 

[waterdrop]

The A-Bacs can appear out of whack for a couple days after water changes like that. Just keep at it and let it settle in for a few days I think. WD

 

[mark4785]

I've been continuing to test but things have not improved for some reason.

The ammonia level still reduces to 0 ppm after 12 hours, but the nitrite level reading is off the scale; when I test for nitrite using the API reagants the colour produced in the vial turns to purple, then green, then grey then to a darker version of cyan.

The PH level is 8.2 and never changes anymore which was something that happened earlier in the cycle.

As a result of the nitrite being so high I've reverted back to dosing pure ammonia every 24 hours and even that hasn't allowed the nitrobacter to reduce the nitrite concentration to any lower level.

Shall I just remove all the water and continue from there?!

edit: I think by the 4th or 5th week into this fishless cycle the nitrite levels were reducing to 0 every 24 hours but it would appear that my 80%+ WC to remove the nitrate has completely upset the cycle!

 

[OldMan47]

Removing and replacing all of the water has worked for many people in the past. It is almost as if the high nitrite levels were preventing the nitrite processing bacteria from developing properly. BTW it has been shown that nitrobacter is not the right bacteria for a fish tank, although it works fine in a sewage treatment plant. For a fish tank, the bacteria are nitrospira. I don't know who really cares though. If your tank is moving nitrites, the right bacteria are present.

 

[mark4785]

Removing and replacing all of the water has worked for many people in the past. It is almost as if the high nitrite levels were preventing the nitrite processing bacteria from developing properly. BTW it has been shown that nitrobacter is not the right bacteria for a fish tank, although it works fine in a sewage treatment plant. For a fish tank, the bacteria are nitrospira. I don't know who really cares though. If your tank is moving nitrites, the right bacteria are present.

Right ok, thanks for that.

I better start removing the aquarium water

 

[mark4785]

I removed all the aquarium water again which brought the nitrite level reading down from a level above 5 ppm (water colour in test tube was grey/brown) to a form of purple which again is not a colour on the API nitrite colour card.

I've resumed putting 2.5ml of pure ammonia in every 24 hours. The effect is that the ammonia reading goes to about 4ppm and within 24 hours its back down to 0ppm. However, the nitrite reading stays persistently at 5 ppm+ and it will not come down!

I'm doing all I can to ensure I cycle the tank properly but it's not behaving itself.

I'm starting to think that something may be causing a stall, but I find that hard to believe as there is only water and pure bicarbonate of soda, along with pure ammonia (which I used to do a fishless cycle on my other aquarium) in the aquarium.

The only thing that I've done differently with this fishless cycle is starting it off with mature pond filter media which was then removed immediately and replaced with new filter media (not ever before cycled). The mature filter media resulted in nitrite and ammonia appearing in the water within a matter of days of adding pure ammonia; from experience I think nitrite only appears in the water after at least 1 week. It's my belief that the colony of bacteria on the mature media has converted an excessive amount of ammonia into nitrite which the new filter media which I'm using now doesn't know how to neutralise fully.

Any help towards getting a solution to this mess?

 

[mark4785]

Any ideas?

 

[waterdrop]

I agree with you that it seems to be a very odd situation and I wish that we had some better idea of what might be causing the problem. I assume we've been something like 3 months then, since going back to having no mature media? The only idea I have at this point would be to perform more frequent full water changes because of the large A-Bac colony producing some much nitrite so fast. Have you tried reducing your ammonia dosing to only 2ppm?

~~waterdrop~~

 

[mark4785]

I agree with you that it seems to be a very odd situation and I wish that we had some better idea of what might be causing the problem. I assume we've been something like 3 months then, since going back to having no mature media? The only idea I have at this point would be to perform more frequent full water changes because of the large A-Bac colony producing some much nitrite so fast. Have you tried reducing your ammonia dosing to only 2ppm?

~~waterdrop~~

Hey,

No I haven't tried to dose 2 ppm as I didn't think that was an option.

I've been aiming for 5ppm of ammonia in 55 litres which equates to 2.89ml. I reduced this to 2.5ml several weeks ago without any positive results.

I've gotten fed up so for the last 72 hours I haven't bothered dosing any ammonia. I've just tested the water parameters and got the following results:

PH: Solution is bright pink??
Nitrite: Purple (off the chart?)
Ammonia: 0 ppm.
Nitrate: 5-10 ppm (not changed for 4-5 weeks).

So the 72 hour pause hasn't changed anything really.

I'm baffled; even dosing a lower amount of ammonia wouldn't correct this problem right?