When Is A Cycle Finished?

[waterdrop]

For our purposes in the hobby (or in the world of fish farms or wastewater treatment for that matter, probably) its easy to get by with symbolic names (like A-bacs or AOBs or N-Bacs or NOBs) and the important things are the processes and so forth. But I do think that in the science, things will slowly advance and putting accurate identifications on what is going on is important and could eventually yield new insights.

I like calling them NOB's, it's the nitrite bacteria that are such awkward little buggers

I only coined the Abac/Nbac thing a while back because BTT seemed to imply that the NOB acronym was somehow embarrassing, so I figured it was UK slang of some sort (you probably shouldn't tell me )

 

[Miss Wiggle]

pm en route........ it's a family forum.

 

[waterdrop]

OK, back to one of our topics about speed of fishless cycling and when fishless cycling is finished...

I want to see if anyone else shares this hunch (just sort of a guess/funny feeling type thing) from following along on so many beginners fishless cycling episodes. I sometimes get the feeling that the water change thing might get even more important as the fishless cycling process gets longer. We've speculated before about whether excess nitrite build-up might inhibit nitrite processing (as a separate problem from there just being a lot of nitrite). I just get this feeling sometimes that after a certain point, water changing a lot of that nitrite and nitrate out of there might somehow help the N-bacs to develop faster. I even wonder sometimes whether a very light filter clean along with a water change at these later stages might help, especially for folks with dead plant material as many fishless cyclers have.

Does anybody share this feeling?

~~waterdrop~~

 

[Miss Wiggle]

definatley if you've lots of dead plant matter inhibiting the filter then you should give it a small clean out, if the flow is restricted then this will limit bacteria growth. so in a long fishless cycle it could help

 

[pastabake]

After reading Walstead's book I'm not too sure that removing all dead plant matter is such a great idea as it seems that organics and DOC play a role in binding metals and other contaminants.

That aside though, going from waterdrop's train of thought I suspect that doing a near 100% water change after you're ammonia spike has come down would be a pretty good idea to get rid of excess nitrite. I'm not too sure about cleaning the biological filter though as unless you have poor mechanical filtration (and you should be regularly cleaning this part during the cycle anyway) its unlikely to be clogged up and over vigorous cleaning could accidentally mess the whole thing up - one of the things you are trying to encourage is not just the bacteria but the extra cellular polysaccharide biofilm that they produce.

 

[andywg]

I'm not sure if it has been published before, but I have actually found what seems to be a full copy of the "Nitrospira-Like Bacteria Associated with Nitrite Oxidation in Freshwater Aquaria" by Hovanec, Taylor, Blakis and Delong which appeared in Applied Environmental Microbiology, January 1998, p. 258-264, Vol. 64, No. 1

link here, PDF here

Just in case anyone wanted to read further into the matter.

 

[waterdrop]

Yes, good idea to link the full article Andy. I'm assuming that's the middle of his three main JAEM articles ('96, '98, '01 I think?) I had read the '96 article early on after I joined TFF and was going on about it when others pointed out that there were the other two. I'm in a university environment so all the articles just pull up easily but sometimes that isn't the case for everyone.

Fascinating the lengths you must go to to identify these things and that you are always working with mixes of species and even that they are changing fast enough that you have to worry about new variations of species all the time. I'm hoping we've got some genuine bacteriologists here somewhere in the depths of our labs and maybe I'll find one someday who won't mind me asking a few aquarium filter questions!

My 11-year-old had me at a review of his schoolwork at the school today and in one of his big science assignments he showed me, with enthusiasm, how he had picked right up on some information they were presenting about the nitrogen cycle - he loved that he already knew all about it. A side benefit of the hobby for him that I hadn't considered beforehand.

~~waterdrop~~

 

[backtotropical]

Good link, Andy.

Here are the other 2 for reference

Comparative Analysis of Nitrifying Bacteria Associated with Freshwater and Marine Aquaria (1996)

Identification of Bacteria Responsible for Ammonia Oxidation in Freshwater Aquaria (2001)

Cheers

BTT

 

[ac700wildcat]

I didn't have the time to read all the pages of this topic and forgive me if this idea has already been suggested, but I do have an idea that I think might possibly also be a good experiment. Take a tank that is cycled and stocked with fish to the 1 inch of fish per gallon rule. Take all the fish out and add a ammonia to say 1ppm to start with and see how long it takes to process it. If its not gone in a day then fish don't produce that much waste. After that ammonia is gone, you add the fish back to the tank and let everything stay normal for however many days, so bacteria population isn't larger/smaller than it was before and then try again with a different amount of ammonia.

Matt

 

[jnms]

I am currently about 5 weeks into a fishless cycle and am noticing something regarding the way the filter processes the Nitrite.

Working with the figures that 1ppm ammonia produces 2.2ppm Nitrite (or 2.7ppm depending on where you look). I recharge the ammonia in my tank to 3ppm every night, this is usually processed within 12hrs or so. 3ppm ammonia should produce around 6.6ppm Nitrite. 12hrs after the ammonia recharge, the Nitrite is down to 1.2ppm - that means the filter is processing 5.4ppm nitrite within 12hours. The remaining 1.2ppm of nitrite takes a further 12hrs to process before it reaches 0ppm.

To confirm this I took the following readings.

Tuesday 10am:
Ammonia - 0.0ppm
Nitrite - 1.4ppm

Tuesday 4pm:
Nitrite - 0.8ppm

Tuesday 10pm:
Nitrite - 0.2ppm

added 3ppm ammonia

Wednesday 10am:
Ammonia - 0.0ppm
Nitrite - 1.2ppm

Wednesday 4pm:
Nitrite - 0.6ppm

Wednesday 10pm:
Nitrite - 0.0ppm

So according to these figures the filter processes around 5.2ppm of Nitrite whilst there is ammonia present. Once the ammonia has reached 0, the processing of the Nitrite appears to slow down, taking 12hrs to process only 1.2ppm

Is there then, a link between ammonia and nitrite - where the presence of ammonia boots the filters capability to process nitrite?

 

[Mr Bliss]

I am currently about 5 weeks into a fishless cycle and am noticing something regarding the way the filter processes the Nitrite.

Working with the figures that 1ppm ammonia produces 2.2ppm Nitrite (or 2.7ppm depending on where you look). I recharge the ammonia in my tank to 3ppm every night, this is usually processed within 12hrs or so. 3ppm ammonia should produce around 6.6ppm Nitrite. 12hrs after the ammonia recharge, the Nitrite is down to 1.2ppm - that means the filter is processing 5.4ppm nitrite within 12hours. The remaining 1.2ppm of nitrite takes a further 12hrs to process before it reaches 0ppm.

To confirm this I took the following readings.

Tuesday 10am:
Ammonia - 0.0ppm
Nitrite - 1.4ppm

Tuesday 4pm:
Nitrite - 0.8ppm

Tuesday 10pm:
Nitrite - 0.2ppm

added 3ppm ammonia

Wednesday 10am:
Ammonia - 0.0ppm
Nitrite - 1.2ppm

Wednesday 4pm:
Nitrite - 0.6ppm

Wednesday 10pm:
Nitrite - 0.0ppm

So according to these figures the filter processes around 5.2ppm of Nitrite whilst there is ammonia present. Once the ammonia has reached 0, the processing of the Nitrite appears to slow down, taking 12hrs to process only 1.2ppm

Is there then, a link between ammonia and nitrite - where the presence of ammonia boots the filters capability to process nitrite?

My guess is that ammonia has nothing to do with this, except in the sense that some of it probably gets processed directly from ammonia to nitrite to nitrate on one pass through the filter. Instead, a lower concentration of nitrite in the water means a lower amount of nitrite is available to the bacteria at any one time and therefore the filter isn't processing it at maximum speed. They can only access nitrite that comes in direct contact with them, after all.

 

[Aphotic Phoenix]

Actually, it wouldn't have to be that expensive or space consuming using: (correct me if I'm wrong of course)
5 - 5 gallon heavy-duty rubber/plastic containers
1 air pump with 5 way split valve + airline
5 sponge filters (cheap and easy to build/replace)

The last part...heat...would vary if one was trying to determine one wanted to test how temperature variances affected bacterial growth. Otherwise, if using fairly heat resistant plastic containers, and under "tank" sort of system that runs along the test area might provide the most even temperature reading as long as the "tanks" were spaced far enough apart that they were not proving insulation for each other. Another option would be an adequately stable room temp.

 

[ldsdbomber]

If you have cycled somewhat but due to an overzealous clean or whatever, now find it isnt cycling as well as it did (i.e if you saw your tank process nitrite from 7.5 to 0.25 in 1 day, and a week later its not clearing 1ppm faster than in 1 day when you are only adding 1ppm ammonia

what is the best route to take (this is fishless cyling)
keep adding ammonia to 1ppm until it processes both ammonia and nitrite in 12 hours, then increase to 2ppm and repeat, then 3 ppm, until you can do 5ppm

OR

whack 5ppm in, knowing full well that you are going to get another big nitrite spike which might last ages (sounds like you can keep changing water though to clear some of backlog).

Having made several mistakes but persevering for almost 2 months with a fishless cycle in a 10g cylinder, am beginning to wonder what I need to do to "get this finished!"

 

[chrisbassist]

fascinating read. At one point I was thinking about setting up a spare tank with NO filter, and getting some fish for it to test how much ammonia was produced (testing at regular intervals, at least every 8 hours) but then thought it was a bad idea since I don't want the guilt of killing fish. (even if it would further the science) Plus if you do that then you have to do it for several different species since they'll all produce ammonia at different ratios to their size. and i'm not prepared to A. spend that much on fish or B. kill them all.

esp since having a cycled and established tank with fish, then taking them out and adding increasingly larger amounts of ammonia each time to see how much is processed will do it without deaths.

I shall be re-reading this topic and then following its progress.

one thing confuses me.

you say "mature" media will double the bac every 24 hours, and new media won't. What is the difference? surely it's just media, and the fact that it's mature just means it already has adequate amounts of bac. and since if it has adequate amounts it should stop producing more, since it doesn't have anough food for any more. Some clarification on that would be great (and sorry but it's a long read, so I can't remember where it was posted...)

 

[fatheadminnow]

If you have cycled somewhat but due to an overzealous clean or whatever, now find it isnt cycling as well as it did (i.e if you saw your tank process nitrite from 7.5 to 0.25 in 1 day, and a week later its not clearing 1ppm faster than in 1 day when you are only adding 1ppm ammonia

what is the best route to take (this is fishless cyling)
keep adding ammonia to 1ppm until it processes both ammonia and nitrite in 12 hours, then increase to 2ppm and repeat, then 3 ppm, until you can do 5ppm

OR

whack 5ppm in, knowing full well that you are going to get another big nitrite spike which might last ages (sounds like you can keep changing water though to clear some of backlog).

Having made several mistakes but persevering for almost 2 months with a fishless cycle in a 10g cylinder, am beginning to wonder what I need to do to "get this finished!"

7.5 ppm of ammonia is nearing the point where the wrong bacteria will began to colonize.

When this happens, one does not know because everything seems to be going along nicely, until one day they add fish or they find out that very little to no ammonia is being processed. This is because this wrong type of bacteria has died off and there are no beneficial bacteria present.