A Thought On Fishless Cycling

[K-Holed]

Afternoon all

I was just having a quick browse around the forums (as I am moved to do, from time to time) and I got to thinking about the fishless cycle. It seems to me that there is often a basic conflict between the desire to add livestock and the need to have a cycled filter.

Now, I may be missing something fundamental but, is there any reason why a filter can't be fully cycled to cope with only half or a quarter of it's final bioload? The general advice seems to be a fishless cycle that allows you (or more specifically requires you) to stock a tank to full capacity in one go. I know that some people like to stock a tank fairly slowly. In some cases due to financial restrictions, other times due to fish compatibility or sensitivity. In cases such as these, would it not be a quicker process to perform a smaller cycle, rather than waiting it out for enough bacteria to cope with a full bioload?

Once again, I mat be missing something huge here but it was just a thought that crossed my mind.

Kind regards

Jimi

 

[erk628]

Well if you follow the fishless cycle using pure ammonia once cycled its pretty much ready for a full cycle. As for the idea of doing half or a quarter cycle goes I don't really see how that would be possible seeing how the cycle process only works one way

 

[Bebobb]

You can't ony "half cycle" a tank. If you only cycled a tank halfway, you would be in the middle of a nitrIte spike. And if you put some fish in during that nitrIte spike, then they will die. I think I kind of understand what you are talking about, but it is not possible.

 

[meguro]

what happens if u dose 1-2ppm ammonia instead of 4-5ppm?

 

[Bebobb]

I'm not sure about that, but I think that when I was reading on fishless cycling, that you can 1-2ppm every day without waiting for the ammonia to go down. Of course this method would take longer (and you probally end up using more ammonia any ways)

 

[Squid]

Meguro is right, he means adding less ammonia. I haven't looked at this for years since I first did mine, but the principle is that if you perform the fishless cycle with 4-5ppm of ammonia, this will cycle the tank for the average bio-load of that tank. In other words, if you filled up the tank with your selected fish, it would be able to cope with that ammount of ammonia/waste. So, effectively K-hole is asking whether it would be quicker to do cycle it for a smaller bioload and then add fish gradually.

I have some mixed and certainly un-validated views on this. If you do the complete bioload and add plenty of fish you can still have issues. The tank is cycled but not mature (see other threads for the difference), and therefore may not support some of your fish's requirements. Some fish prefer a tank that is more mature, and you are therefore better off waiting before adding them anyway. A cycled up and running tank can take the addition of fish without noticing too much in the way of a mini-cycle, so I guess it may depend on the percentage of fish you add up front, and then the percentage added in stages. This kind of makes you think that you could be right, but I think it is probably safer to exceed the bio-load to an extent anyway.

It is also my belief that the bacteria, once colonised, can multiply fairly quickly, and that most of the time is spent waiting for the initial colonisation. If you think about it, it can take a similar length of time to cycle a 50 gallon tank as a 10 gallon tank. Therefore the amount of time saved by using less ammonia and cycling the tank less might not be much anyway.

So, in summary, for the ammount of time saved and the benefits of supporting a greater bioload from a certainty perspective, i would probably stick to the full amount.

Does that make sense, as these look like the ramblings of a mad man.

cheers,
Squid.

 

[K-Holed]

@Beta Boy/erk628 - Sorry maybe I wasn't being clear enough. I wasn't suggesting "half cycling a tank", that would just be silly. What I was interested in was the possibility of a full cycle with a lower concentration of ammonia.

@Squid - Yes, I think you've probably hit the nail on the head. I have no idea why I was thinking that the colonisation of the bacteria would be on a linear scale, it's exponential. So I think you're right, once the colony got to be a certain size it would be doubling very quickly. Hence the reason why you can add fish slowly to a cycled system, without a spike, in the first place.

*Mental note* Engage basic GCSE biology before posting

 

[AdamM]

ive always wondered if it would be possible not only to dose ammonia, but also NO2? so that your building up both bacteria at once?

 

[Amberleaf]

Yeah; I agree with AdamM.... Although, what some people (including me :3) like to do is only stock a tank to, say, a 3rd of it's full bioload -- if a 10-gallon tank can support up to 10 2-inch fish, then you simply add 3 fish, and if they're livebearers, then over time, fry will be born, and since they don't necessarily produce a *huge* bioload, then the bacteria will grow with the babies. Or somethin' like that.

 

[OldMan47]

The biggest problem that I see with cycling a tank half way or 1/4 or something is the end result. Since the bacterial colonies can more or less double their population in a day, the 1/4 cycled tank would become a fully cycled tank in just 2 more days. Why not finish things up when you have spent 6 weeks getting that far?

 

[drobbyb]

Less ammonia can't speed up the colonization and growth of bacteria. It takes the same amount of time to grow both the larger and smaller set of bacteria. The only thing you would save was a few ml of ammonia.

AdamM, that's a very interesting hypothesis. If I had 2 empty tanks, I would try it to see if it was indeed possible. Anyone fancy an experiment?

 

[AdamM]

Less ammonia can't speed up the colonization and growth of bacteria. It takes the same amount of time to grow both the larger and smaller set of bacteria. The only thing you would save was a few ml of ammonia.

AdamM, that's a very interesting hypothesis. If I had 2 empty tanks, I would try it to see if it was indeed possible. Anyone fancy an experiment?

i would but, having mature media my new tank was cyled in a few days, sorry very interesting though.

 

[Amberleaf]

But wait isn't nitrite a by-product of ammonia or something? Which would mean if you dosed both at, say, 5 ppm from day one, the nitrite would still spike, and go higher than 5 ppm? Just a thought.

 

[AdamM]

the first bacteria turn ammonia into nitrite, but it takes time for the bacteia to build up, but if you dosed both, the nitrite-nitrate bacteria would grow at the same time, and they would actually have more that whatever you dose, because of the eventual stuff from the ammonia... so you would end up with a stronger population

 

[erk628]

the first bacteria turn ammonia into nitrite, but it takes time for the bacteia to build up, but if you dosed both, the nitrite-nitrate bacteria would grow at the same time, and they would actually have more that whatever you dose, because of the eventual stuff from the ammonia... so you would end up with a stronger population

Would that mean that it would cut the cycling time in half? Maybe even a little more then that since it seems when the nitrites spike it takes longer to come down then the ammonnia did.